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The Super-Plinker/Best of both worlds.- DIANA 280

8/6/2021

G'd I miss IWA!

Every year the pilgrimage to the greatest "Weapons Exhibition" in the world is a thrill.

And, of course, spending some real-face time with my DIANA friends is a boon to boot.

BUT CoViD19 put a damper on IWA 2020 and IWA 2021, next year IWA 2022 has been programmed, but there is no guarantee.

Anyway, one of the more charming aspects about IWA is that you can interact with top notch gunsmiths from around the world. Not all are interested in airguns, but most of them understand the complexities of low power shooting.

Among the typical discussions is the eternal one about the "German" way and the "American" way. From sling placement and usage, to sights and stock shapes, there is always someone that claims to be "richtig" & "genau". :-)

Of course the reality is that we need to take the best of all the options available to us. And this post is a bit about that: Getting a German, medium powered springer to be a joy to shoot in a specifically American endeavor: Plinking with iron sights using economy pellets.

So, when a friend requested something to complement his scoped R-7, I thought: This is a good opportunity for a DIANA 280.
And so the project started some months ago, the guns were available then and they were procured.

One, in 0.177", cal has already been reviewed here.

And the challenge with this one in 0.22" cal was to make it shoot well with iron sights.

We went back and forth with different rear sights, but in the end, it was necessary to change the front sight to something that would allow proper head positioning, BUT, we still wanted to keep the gun as DIANA as possible, and so we changed the front muzzle piece to one that was made by DIANA for the larger guns to use the "Korntunnel" in the DIANA lineup.

However, there are no Fiber Optic korntunnels in the German world, ¿What on earth for? you are supposed to shoot ONLY at paper targets! You NEED BLACK! . . . . LOL! . . . Nope!
Enter Tru-Glo, an American company that has been making optical gathering front sights for some time.

That allowed us to use the Williams FP rear and add the Merit Iris for light and contrast control, but since the sight stop is located fairly forward, an extension to the eyepiece had to be manufactured.

The powerplant was changed to a Titan #10 spring in a custom composite guide; performance stats are located in the targets for those that need numbers.

Overall it was a great project, fun and challenging.

So, let's look at some pictures:

The first thing we did was to shoot the gun in, with the normal shoot and clean routine, this took some weeks of intermittent effort. We then shot some test groups to define the best pellet. Without a doubt, the JSB RS proved to be the one. This is a no-standard 10M target because of the colors, but the size is strictly regulation.

But the gun had an extremely low LOS, and the stock was completely inadequate. It took great effort and concentration to shoot groups like the one above, so we installed a small, appropriate telescope and tested other pellets from among the ones that ARE available.

Results were reasonably good, specially the H&N Excite Hammer, that is an "economy" pellet in the H&N line.

But the owner insisted on "Irons" as the gun was to be a "plinker". And so. we decided to test the flat Match style muzzlepiece DIANA makes for the 48->54 family, that did not look bad at all.

The space between the relatively thin barrel (15 mm's) and the external bore of the muzzlepiece cavity was taken up by a "Cello" finish Carbon Fiber tube.

At the rear, we installed a Williams FP/AG sight, but had to use the long slide of the GR sight to really give it latitude.

But the rear sight was too far forward to give a good sight picture! We had to make an extension.

This is the sight picture through the Merit Iris disc once the extension was added. You can clearly see the bright aimpoint from the TruGlo front sight, even against a white paper.

And then we took the gun to play outside!

After some warming up and sighting in at a more realistic distance of 25 yards, these are the results.

One of the things I really like about the Tru-Glo is that the amount of light you put "on target" is adjustable. You can reduce the brightness in an extremely bright day to a good level by turning the "shading" on.

Or you can have more and more light by "opening the shutters".

If there was truly little light in the day, then you can have a wide open window, taking in light from almost 180° of sky

This is the sight picture with a "fully closed shutter", yes it is bright, but by no means glaring.

And I do like the way the CF glossy finish tube shines! LOL!

In the end, this is what it is all about: a pleasant evening in the cooling day, with your S.O. so that she can create the targets for you. Some distance, some pellets, and have fun!

And if you REALLY have what it takes, then turn the can on end. The gun is more than capable. Will you be? ;-) Let's see!

Keep well and shoot straight!

HM

17 Comments

Shot cycle Dynamics in 3 Spring-Piston Airguns Chap 9 NEW-NEW

8/5/2021

3 Comments

Conclusions: What does all this means?

I consider myself lucky if I can learn something new every day. In preparing, writing, and discussing the previous eight chapters, I have learned a great deal, sometimes more than I bargained for! Before I start drawing conclusions, I’d like to spend some time on an important lesson that I learned after these chapters were posted, and that is how to (or better yet, how not to) measure the recoil of air rifles. One of the key points of discussion has been the limitations of using a sled to measure air rifle recoil. The sled is convenient, allowing one to easily measure different rifles, but has two major drawbacks, one of which I was aware of before we began testing and the other was brought up by Steve in NC. The first limitation of the sled is that it adds about 2.4 lbs to the recoiling rifle, which will change how the bare rifle recoils. This is not too big a deal, especially for heavier rifles where adding a couple of pounds doesn’t make that much difference, and will simply scale down the measured velocity and acceleration. One could make the argument that when an air rifle is shot from the shoulder, parts of the shooter also move with the rifle, which adds to the recoiling mass and therefore will help tame the recoil. The second limitation was brought up by Steve in NC, and it has a more pernicious impact on our measurements. Steve aptly pointed out that when the piston decelerates, stops, and starts moving backward due to the highly pressurized air in front of it at the piston bounce, air rifles typically accelerate forward at a few hundred g’s (multiples of the acceleration of the earth’s gravity, 9.8 m/s2 or 32 ft/s2). To also get the sled to start moving forward, the rifle has to pull the sled with hundreds of pounds of force, albeit for a very short amount of time. Unfortunately, the only way the rifle can pull the sled forward is with the Velcro strap that holds the rifle against the back stop of the sled. Velcro is strong, but a few hundred pounds of force will certainly cause it to stretch and therefore the sled will not instantaneously move forward with the rifle. Since the magnet and pickup coil are attached to the sled and sled base, respectively, and not directly to the rifle, we are measuring the motion of the sled, which is not exactly the same as the motion of the rifle if the rifle moves on the sled when the Velcro stretches. In order to overcome these problems, I built a brand new cradle system and will discuss the new results in this chapter.

Figure 9.1 shows the original sled system. A metal plate from the butt of the rifle (not the rubber buttpad) pushes against a wooden stop at the back of the sled, so I think that the initial rearward acceleration of the rifle should transfer to the sled pretty well. However, when the rifle accelerates forward it pulls the sled with it using the black Velcro strap. At the piston bounce the forward acceleration of the air rifle is on the order of hundreds of gs. Remember that force equals mass times acceleration, so to get the sled moving forward and accelerating in unison with the rifle, the force on the sled through the Velcro strap needs to be hundreds of times the weight of the sled. If the sled were very light, it would be very easy to accelerate it forward with the Velcro strap, but since the sled weighs about 2.4 lbs, it takes hundreds of pounds of force to get it to accelerate forward.

Fig. 9.1 Photo of sled recoil system. The rifle is pulled back against the rear stop of the sled using the Velcro strap. When the rifle accelerates forward with hundreds of gs at the piston bounce, it will pull the sled forward with the Velcro strap, stretching the strap. Please note that in this system we are measuring the velocity of the sled.

Figures 9.2 and 9.3 show the new cradle that I recently built. The top part of Fig. 9.2 shows the overall setup. The rifle recoils in a stationary cradle under the forearm of the rifle. The forearm of my DIY LGU stock is rectangular, so it’s very easy to support it with two blocks of wood. The permanent magnet is attached directly to the rifle via a scope base on the scope rail and the pickup coil is positioned using steel rods to be directly behind the magnet. I’ve added a DIY contact microphone (https://www.instructables.com/Make-a-Contact-Microphone/) on the receiver near the trigger. This serves two purposes. First, it provides a strong and reliable signal to trigger the oscilloscope. The clicking of the sear when the trigger is pulled, creates a sound that is picked up by the microphone and this signal is used to let the oscilloscope know when to start taking data. This is the first time that I used a rifle trigger to trigger an oscilloscope! The microphone also provides useful insight into what is going on inside the rifle. For example, it literally hears not only when the sear falls, but also when the piston bounces and when it lands at the front of the compression tube. In front of the rifle is my DIY chronograph with its two light gates (LG1 and LG2). When the pellet passes through LG1 and LG2, positive voltage pulses are produced that are recorded on the oscilloscope. The time interval between these two pulses can be used to determine the pellet velocity using the fact that the gates are 1.88 ft apart. Once we know the pellet velocity, we can determine the time it took the pellet to travel the 6” distance from the muzzle to LG1. This time is subtracted from the time when the LG1 pulse occurs, allowing one to determine the time when the pellet exits the air rifle muzzle. Since we know when the sear falls using the microphone signal and when the pellet exits the muzzle using the light gate signals, we can determine the pellet dwell time in my LGU, which was around 10.0 ±0.3 milliseconds. The bottom part of Fig. 9.2 shows a close-up of the cradle channels, which are lined with plastic pieces that were cut out from furniture slider pads to provide low friction contact with the stock. The width of the channels is adjustable.

Fig. 9.2 The overall setup using the new cradle system is shown at the top of this figure. The pickup coil is placed behind the permanent magnet, which is attached to the rifle’s scope rail using an aluminum rod and a modified scope base. A DIY contact microphone is mounted on the receiver near the trigger. In front of the rifle is my DIY chronograph with its two light gates, LG1 and LG2, which are used to measure the pellet exit time. The rifle slides in the two cradle supports. A close-up photo of the cradle supports is shown in the bottom of the figure.

Figure 9.3 shows a close-up of the recoil measurement system. The permanent rare-earth magnet is glued to the end of an aluminum rod, which is screwed into a modified scope base that is attached to the rifle’s scope rail. The system easily can withstand over a hundred pounds of force and still remain securely attached to the rifle. Of course, since the combined mass of the scope base, aluminum rod, and magnet is only 30.0 grams, only about 13.5 pounds of force are required to accelerate them in unison with the rest of the rifle, even if the rifles accelerates with 2000 m/s2 (over 200 gs!). The pickup coil is stationary and is positioned directly behind the permanent magnet. I used rods and clamps to allow the position and orientation of the pickup coil to be securely and easily changed, which will help when different rifles are placed in the cradle.

Fig. 9.3 A close-up photo of the velocity measurement system for the new cradle setup. The pickup coil is placed behind the permanent magnet, which is attached to the rifle’s scope rail using an aluminum rod and a modified scope base.

Figure 9.4 shows the old and new recoil traces. On the left one can see the recoil that was measured with the old sled system. The red trace in the middle shows the sled velocity as a function of time. The orange trace right below it shows the light gate signal, with the red vertical lines indicating when the pellet exited the muzzle. The top graph shows the position of the sled vs. time and the bottom graph shows the acceleration vs. time. The right part of Fig. 9.4 shows the recoil traces that were obtained using the new cradle system. In addition to the position, velocity, and acceleration of the rifle itself, I also plot the contact microphone signal at the top. The microphone signal shows a large initial pulse (trigger sear noise), then a smaller pulse (piston bounce, PB), and then two large pulses (piston landing at the front of the compression tube for the first time PL1, bouncing back and then landing again PL2). We can learn a lot when we just listen!

Fig. 9.4 Recoil traces using the sled on left, and the new cradle setup on the right. In addition to recording the velocity of the sled or rifle, from which position and acceleration are determined, we also record the light gate signal to determine when the pellet exits the muzzle. With the new cradle system, I also simultaneously recorded the signal from the contact microphone, which is plotted at the top of the right column. The microphone allows one to “hear” the sear breaking, the piston bounce (PB), and the first and second piston landings (PL1 and PL2).

The velocity and position traces are qualitatively and even quantitatively similar using the two measurement systems. With the sled system, the position trace is much more rounded, smoother and the dips are shifted to longer times. Also, the sled goes back 4.5 mm before stopping while with the cradle system the rifle goes back only 4.0mm. Another difference is that the sled goes forward a much greater distance after the first stop compared to the rifle in the cradle. The sled almost gets halfway back to its starting position, while the cradled rifle moves forward less than a millimeter after the initial stop. The greater movement of the sled is probably due to the lower friction in moving the sled compared to moving the rifle in the cradle. The smoother, rounder, and delayed dips are due to slop in the connection of the rifle to the sled via the Velcro strap, as will be discussed below.
The red velocity traces in the middle of Fig. 9.4 also are similar, with an initial dip as the rifle and sled recoil backwards, a forward peak as the rifle and sled move forward, and some oscillations after that. The maximum rearward velocity of the sled is around 750 mm/s, which is similar to the value obtained using the cradle. This is probably due to the strong connection of the rifle to the sled when the rifle is pushing back. On the other hand, the first dip in the velocity with the sled is symmetric while the right side of that same dip is much steeper with the cradle system (see purple ovals in Fig. 9.4). Furthermore, the magnitude of the peak forward velocity using the sled system is about a factor of two bigger than with the cradle system! The most critical difference is that the pellet exit time with the sled occurs before the sled stops (v=0), while it occurs after the rifle stops using the cradle system. The reason for this is that with the sled, the rifle stops and starts moving forward well before the sled gets accelerated forward by the stretched Velcro strap. As a result, the sled stops after the rifle stops, so the zero in the sled velocity occurs later, after the pellet has exited the muzzle. The pellet actually exited the muzzle after the rifle stopped, but since we’re measuring the motion of the sled and not the rifle, we do not measure this correctly. This is probably the biggest problem with using the sled. The extra forward motion of the sled could be due to the stretched Velcro causing the sled to snap forward and hit the back of the rifle, giving the system a delayed, extra push forward. The lower friction of the sled could also allow the amplitudes of the position and velocity oscillations to be bigger compared to the rifle sliding with more friction on the cradle.
The bottom traces in Fig. 9.4 show the acceleration of the sled (left) and the rifle in the cradle (right). Here the differences are most dramatic. The slop in the connection between the rifle and the sled, especially when the rifle is going forward and relies on the Velcro strap to pull the sled forward, results in broader peaks and dips with much smaller magnitudes. The peak forward acceleration at the piston bounce with the sled is around 200 m/s2 while it’s closer to 1500 m/s2 with the cradle! Thanks to the new cradle data, we can see that the piston landing is more violent (louder, as seen in the top microphone trace, and with a bigger acceleration) than the piston bounce. I guess a cushion of compressed air is gentler in stopping the piston than the steel end of the compression tube! It's very helpful to measure the sound in addition to the velocity and pellet exit signals. The more we can measure the less we have to guess about what is going on!
The problems with the sled system will corrupt the recoil traces, especially the acceleration. However, since we use the same sled system to characterize and compare all three air rifles, the relative differences in recoil behavior can still provide insight into their behavior. Ideally, we would use the new cradle system for all these measurements, but that will have to be a future project.
Although I strive to learn from other people’s mistakes, I often learn more from my mistakes than from my successes, and this mistake has been very educational! My understanding of how an air rifle recoils and how to measure it has dramatically improved thanks the revelations that Steve made!

So here are the conclusions, finally!

This series of chapters has been a long journey for me, that is still ongoing. I have learned a great deal, but still have a lot to learn. I have drawn four basic conclusions from this work:

1. Airguns are fascinating! You probably wouldn’t have made it through the last eight chapters if you didn’t agree with this, but I have gained an even greater appreciation for the engineering and physics involved in air rifles. I’m still amazed that a bouncy mechanical system can put 10 pellets within a quarter inch of each other at 20 yards. The spread of pellet impacts corresponds to an angular separation of less than 0.02 degrees. That’s an angular resolution of 1 part in 18,000! Even more remarkable is the fact that my forty year old FWB 124, with its break barrel, can match the accuracy of modern underlever air rifles, built in this century! For a break barrel to achieve this kind of accuracy, the muzzle of the barrel needs to repeatably return to the same position within 0.006” when the barrel is closed. And this is done with a simple ball detent to lock the barrel in place. I wouldn’t be surprised if most barrels have a runout from one end to the other that is at least a few thousandths of an inch. This accuracy is achieved in spite of fairly violent recoil motion, with the rifle moving almost a centimeter back before the pellet leaves the barrel in the artillery hold. Figure 9.5 shows some of the best 10-shot groups that I have ever shot from a springer at 20 yards. In Fig. 9.6 you can see how my LGU did at 52 yards outdoors. The groups all have a similar POI, especially the first and third groups, which are right on top of each other. These groups would be pretty respectable for a 22 rimfire rifle, so I’m very happy and a bit surprised by the performance of my LGU at 52 yards.

Fig. 9.5 Eight 10-shot groups from my LGU off the bench at 20 yards. The composite group on the right overlays all the groups on top of each other using the aiming square and demonstrates that all eighty shots landed inside a circle with a diameter of 0.60”. The ctc distance for the 80-shot group was a 0.45”.

Fig. 9.6 Some more recent groups from my LGU off the bench at 52 yards. These are 10-shot groups, with ctc distances of 0.72”, 0.89”, and 0.62”.

2. Don’t trust a single target group! The computer simulations and more extensive target testing has convinced me that one cannot judge the accuracy of a rifle based on a single group. Completely random fluctuations can easily produce tiny groups, especially if the group consists of five shots, but also for 10-shot groups. I also learned that my simple ideas of statistics do not apply to groups at a target. The group size does not grow simply as the square root of the number of shots, as one would expect for a normal distribution. In hindsight, this makes complete sense since all rifles have a point of impact envelope (POIE) in which they can pretty much keep all their shots, so we should not expect group sizes to simply grow without limit as the number of shots in the group increases.

Figure 9.7a) shows four 10-shot groups at 20 yards from my LGU. The first three groups are pretty typical, but the last had a ctc of around 0.090”. This is pretty remarkable, but unfortunately does not reflect what I can normally expect out of this rifle. If we can get a remarkably small group for 10-shot groups, mostly by accident, the likelihood for getting a tiny but non-representative 5-shot group is even greater. Figure 9.7b) shows largest and smallest five-shot groups out of a total of twenty groups that were generated completely randomly on a computer. One can pretty easily get a difference of nearly a factor of two in group sizes for purely random groups, so when I get a super tiny five-shot group, I have to wonder if it may have just been luck.

Fig. 9.7 a) A tiny group and some more typical groups from the same rifle under identical conditions. b) A big and a tiny group randomly generated by a computer under identical conditions. My LGU has produced groups as small as 0.090” at 20 yards, but I’m afraid that this isn’t typical. If I create 5-shot groups on a computer, there’s a pretty good chance one group ends up being half the size of another group.

3. Physics and math let us see what is normally unseen! It’s fun to tinker with and shoot air rifles, but it’s even more exciting and interesting to try to understand their behavior in more detail. The recoil of these rifles is complex. I found it especially exciting that some basic analysis of the overall recoil of the rifle gave us important quantitative information about what the piston, which is hidden inside the receiver tube, is doing. For example, we can estimate the piston speed as a function of time. If we had better data and analysis on what the mainspring is doing we could even obtain the piston position as a function of time. This in turn can give us the pressure and temperature of the air inside the compression chamber on a sub-millisecond time scale. I also learned that the pellet leaves the barrel in about 10 milliseconds, right when the piston is making an abrupt stop near the front of the compression chamber. Although we like to have smooth, buzz free spring piston air rifles, the strong recoil oscillations after the pellet leaves the barrel do not affect accuracy, so maybe we shouldn’t worry about them as much? I also hope that these chapters help remove some of the stigma associated with tools that shoot projectiles! My family and I spent a year in Munich Germany a few years ago and my son’s choir group went on a field trip to an airgun club to shoot airguns at 10 meters. It would be hard to imagine something like this happening in the USA! One of the senior choir teachers was an avid air rifle competitor and she made it clear that the airguns in her club were not weapons but were really sports equipment. There are quite a few Olympic sports such as the biathlon, archery, fencing, and of course target shooting that have martial origins, but now are highly competitive and demanding athletic endeavors. Airguns are also widely used for hunting. Of course, airguns can be dangerous, but when they are handled responsibly, they can be extremely beneficial, and can perhaps even be used to learn (and appreciate!) physics and engineering!
Figure 9.8 shows the position, velocity, and acceleration of an air rifle as a function of time. It also shows when the pellet left the barrel and records the sounds that the rifle made. There’s a lot of complex and interesting information here, but the challenge is to figure out what it all means!

Fig. 9.8 By measuring the velocity of the recoiling rifle as a function of time using a pick up coil, one can “see” how the rifle moves when it is fired. Using the new cradle system, I measured velocity of the rifle in the center plot, and using calculus was able to determine the position (top plot) and acceleration (bottom plot) of the rifle as functions of time with sub-millisecond time resolution. I also record the light gate signal to determine when the pellet exits the muzzle. Using the contact microphone signal (plotted at the top), one can also “hear” the sear breaking, the piston bounce (PB), and the first and second piston landings (PL1 and PL2).

4. It’s the people! I’m glad that I wasn’t alone on this journey of exploring air rifles, and in fact if it weren’t for my fellow air rifle shooters whom I’ve befriended over the years, I’m sure that these chapters would never have been written! I had a lot of fun working with Hector and Willem on these chapters over the past year and really appreciate their help in making sense of it all.
I have greatly enjoyed and benefitted from talking with fellow airgunners from all over the world. A great example was my experience at my first Pyramyd Cup in 2019 (see Fig. 9.9). I was having some technical problems with new equipment and at the end of the first day of competition, many of the people that I was competing against spent their limited free time to help me. Several of these people were national and international champions in FT, so it was wonderful (albeit a bit embarrassing!) to have a group of FT veterans working with me to get the technical problems sorted out before the match continued on the second day.

Fig. 9.9 Photo of Nathan, Hector, and me at the Pyramyd Cup in 2019.

I’ve also made some valuable new friends as a result of this blog! I’ve enjoyed some very technical and informative discussions with Steve in NC. Thanks to his excellent questions, I’ve learned a lot more about how springers work and how to measure their behavior. Thanks to this blog, I’ve established a connection with one of my springer heroes, Jim Tyler. Jim has been an inspiration in my work on testing springers. All my recoil measurements are based on the system that he invented, and in the final measurements I used a recoil cradle just like he's been doing for many years. I have read all his Technical Airgun articles in Airgun World since 2009, which is as far back as I can get in the digital archive. Jim has probably forgotten more than I will ever know about springers, and yet he has been extremely gracious, friendly and modest in all the excellent help that he has given me.

I hope that you have found these chapters interesting and that they stimulate more discussions and new friendships!

JC
Aug/2021

3 Comments

Nur für Jäger / Only for hunters.- Take TWO

7/29/2021

1 Comment

Some things come out of the blue.
Unexpectedly.
Suddenly
And challenge your "mettle".
Such is this case.
Some months ago, I was contacted by a person that had not shot before (this is important!). But had decided to get rid of invasive pests using an airgun.

So far so good, right? NOTHING out of the ordinary!

Well, because of the disruption of the supply trains of EVERYTHING due to the Pandemic, the ONLY gun he had found was a Hatsan FlashPup QE.
As far as I was concerned, he could have been talking in Martian! Hatsan? yes, check! I know they make guns, but have never taken them too seriously after venturing into one of their power-monster-springers.

And this guy was telling me he was happy with a PCP!

That he had been shooting squirrels and pesky birds.

But that now he needed a "scope or something".

Hmmmmmm, quickly look into the Hatsan lineup and yes, there are the PCP's; and there are the Flash'es; and there are the bullpup versions, ergo: FlashPups; BUUUUTTTTT, they have NO SIGHTS!

"Ehem, ehem, ehem, sorry, sir, but have you been shooting an airgun without ANY sighting equipment?"

"Yes, and I am hitting rather well, but by now the critters are learning that the "pfft" precedes the decease of a mate, and they have started to fly as soon as the window opens".

WOW! I must have been silent for more than a few seconds because the voice on the other side of the phone asked: "HELLLOOOO! You there still?"

"Yes, yes, yes, of course I am here it's just that you are the first person that I have met that has chosen to shoot a bullpup gun in 0.25" cal yielding well in excess of 28 ft-lbs without sights!"

and without skipping a beat he goes: "Yes, that is why I need some sort of sighting equipment, what do you have?, I live in Connecticut and I thought I would swing by and see what we can put on the gun"

Ooops!

"Sorry sir, we used to live in Connecticut, but we now live in Maryland. We moved about 4 years ago".

"Ahhhh, I really wanted to chat with you and see if you can teach me how to shoot properly"

Properly? this guy is hitting stuff without sights! What can anyone possibly teach him?

Anyway, to cut the story short, he mentioned that he had some issues with the gun, that, at first it had been shooting very well, but that a few weeks before something had gone wrong and he was not able to hit anything.
He suspected the gun needed cleaning, but he just could not find a way to do it.
Lots of questions with no answers till I could get my paws on the gun.

So . . . The gun was shipped and put in the queue. And as time passed, its turn came.

So we started talking again about the gun itself, the purpose and the future.

After a good conversation we agreed that I would test the gun and see if it was in any way "not 100%", and that after that we would agree on course of action.

Initial tests were somewhat disconcerting, the gun would yield 100 shots with more than reasonable consistency, but at too low power (under 10 ft-lbs). Yet, nothing seemed to be wrong with the gun.

After a few air top-ups with my battery driven compressor it became apparent that the tank was loose in the chassis.

So I took the gun apart and found that the looseness of the tank was really that the tank had backed OUT of the action and therefore the power was very low.

Two ORings had been "overenthusiastically" installed at the plant and the process had sheared off more than ½ section of each.

So, they were replaced, everything put back in place and the gun tested again.

What a difference!

After the "fix" the power jumped to well over rated power

We also took advantage of the take down to reduce the grittiness of the trigger, there is precious little we can do about the "mushiness" because as many bull-pups there is a transfer bar that connect the trigger blade to the actual trigger mechanism:

When disassembling these linkages, ALWAYS remember that assembly is right to left, so disassembly is always left to right (along the main axis and direction of the muzzle).

This really thin connecting rod is what links the trigger you pull with the actual trigger levers and sear in the rear.
It is important to note that the rear connection is RIVETED, so it is better to disconnect the forward conneciton point (see above).
Once the trigger linkage was out of the way, we could access the screws that attach the tank to the action.
And the screws that govern the trigger behaviour.
While there are many plastic parts in this gun, that is not a low quality indicator on the parts.
What was low quality was the time dedicated to the assembly. There is no excuse for cutting ORings at the assembly point.
One thing I liked VERY much is the substantial bolt handle.
It brings back a familiar feeling long missed.

The gun is an interesting gun, and in many ways replicates the performance of the Talon that was equipped with the first Opteck scope to be mounted in an airgun in the USA.
It was interesting, but not completely unexpected, to see the JSB's perform better than the others.
What was unexpected is that the Predators performed so much better than the Kings.

Now, given the MV's and the energies involved, I opted to suggest my new-found friend, an Opteck scope with a built in laser rangefinder, it is ideally suited to take shots at different things/distances with a stable platform, that will ensure a clean, quick and humane kill.

As a reminder, the Opteck scope was reviewed in the first take of this same title: "Nür fur Jäger"

The only update I've done to the system is that now a rechargeable battery is supplied:

It's good for a full day of shooting and recharges from any USB supply

If we compare the FPQE to the Talon:

You can see there is not much size difference between the two platforms, the Talon is a bit longer and more svelte, the FlashPup QE is more compact and stodgy.

Truth is they both handle well in the field.

There is not much forearm in the FPQE to put the scope's remote control, so it had to go to the back, where the forward hand can come back and push the rangeing button.

Because of weight distribution, I decided to mount the smart mount "backwards" and this allows better mounting position and more latitude, should the owner decided to choose a different mounting position.

Where there is a substantial difference is in the weight!

There is a full 1 lb 2 Oz difference when the all-up weights are compared.

Yes, one is a single shot, the other is a repeater. PERSONALLY, I don't value that aspect too much, but to each his own.

There is a fair amount of pellets available in the caliber, but the gun seemed to prefer pellets in the 25-27 grains region; too light and it would not develop more MV, too heavy and the same would happen.
Probably, this makes these guns prime candidates for regulation. But usually, that causes a drop in ME.
With the size of the tank in this gun, it seems quite possible that a proper regulation could be performed as long as the barrel is swapped (and possibly the moderator altered).
HOWEVER, for the price point of this gun, I was very impressed at the uniformity and efficiency of the strings as long as the optimum weight for the valve setting was respected.

At 25 meters, the gun showed again a marked preference for the Predators, though there COULD be a way to make the gun shoot better with the other good candidates, like he SuperH Points and the BHE.

Tests to determine the trajectory of the better choices proved more than interesting:

But with the pellet scarcity now in effect, and Predators becoming "unobtainium", in the end we had to retest and make it work with the Kings:

The group of 10 shots at 50 meters tells us that the valve has its limitation as far as repeatability. An obvious solution is regulation, though the architecture of the tank would seem to imply that it would be wise to partition the tank into ¼'s and allow a full ¼ as a "plenum".
Don't know if I will ever do this, but it is an interesting idea.

If the proof of a pudding is in the eating, then the proof of a hunting gun is in the shooting.

Once the data was put into (the now de-published) PP-Calc, the trajectory showed this for the holdoffs:

And so, I decided to setup a hunting target, pick up the rifle (that showed about 50 BAR's remaining useful pressure) and, without any further preparation, shoot from different spots in the backyard ONE shot each from different distances and angles:

Shot #1 @ 35 meters was good, a bit high, but good.
Shot #2 @27 meters was also good, though the wind kicked in, the 0.25" cal is reasonably resistant to drift.
Shot #3 @ 43 meters showed that the wind drift resistance disappeared when the wind changed direction completely! however, the elevation for the shot was good.
Shot #4 @ 52 meters was bit affected by the wind, but it would have still been a good shot.
Shot #5 @ 12 meters was taken quickly (under 3 seconds) and just taking the time to rangefind and without focusing, taking the offhand shot. Was IMHO, a good shot.

The system therefore acquitted itself quite nicely.

For the time being, the rifle will be used with Kings, when the Predators become available, we will follow the same procedure and determine the proper hold-offs.

Having finished the technical side, it became necessary to solve one of the main worries: How to clean this gun?!

There is precious little space (15½ mm's) in the breech to insert any kind of cleaning instrument.
And the front end really should not be messed with much, any misalignment there will change the POI and you really do not want to do that.
So I decided to make my own solution:

This is a simple loop of weedwhacker line inside a clear plastic tube.
This allows the "loop" to be inserted from the muzzle without any risk to the rifling and, especially, to the crown.
The loop can almost be retracted into the tube:

And at the far end, whipping/serving keeps the two sides together and gives a good hold to pull:

To use, you create a "Taco" using an OTIS patch and a square small caliber patch:

That you can put through the loop once you have inserted the tube bearing the loop from the muzzle:

And then you pull:

You can then turn the "Taco" and use the other side:

Which gives you a bit more cleaning from the same patch:

After using the two sides, you turn over the patch, using the same "core" and repeat. So for every patch you get 4 strokes.
After 3 patches, you get a reasonably clean bore:

Last point in the agenda was to send back the gun properly outfitted, and so a hard case was procured.
MTM (the ammo box people) make this case and it was interesting because it was just long enough and seemed sturdy enough for shipping and storing.
Some reviews criticize the case, but clearly they did not take the time to read the instructions and fit the straps.
Once you do what your gun needs, the case is sturdy enough, it won't allow the gun to move inside the case.
And so, the FPQE is going home. A different creature with more poise, more reach, and better behaviour:

I enjoyed this project very much. With this scope we reach the half dozen installed in different airguns, and all the owners seem to be happy.

Keep well and shoot straight!

HM

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Simple Field Target #3.- FTRPA July 18th 2021

7/23/2021

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Preamble and Acknowledgements

This "Simple FT" thing' is becoming a habit (or is it an addiction?) ROFL! a good one at that.
It forces you to always start from the basics, if you forget the slightest thing, BOING! there goes a shot where it should NOT have gone. And you only have yourself to blame.
Demanding? Yes! but we spring-piston shooters love the challenges!

So, when the Falls Township Rifle and Pistol Association (FTRPA) FT team posted that they would be hosting a shoot in July, I quickly obtained permission from the "High Command" and got my license for "R&R", LOL!

Hotel booked and everything settled, the trip started after a Saturday full of activities with the kids and wife.
The drive was somewhat annoying. Gone are the days of little traffic due to Pandemic's partial lockdowns; statistics say that we are back, if not above, Pre-"Year of the Masks" levels of travel and traffic; the Hospitality Industry has even coined a term: "Revenge Travel" where people travel just to travel, to feel free and unfettered by quarantines and isolation rules.

SOooooo.... After three different traffic jams and an almost 5 hours drive, I arrived into Ewing, NJ to spend the night.

Morning after, I headed to Fairless Hills, where FTRPA is located, just 17 minutes from the hotel. Funny how some states have much better economic policies than others, and it is a pity that PA does not realize how much business is lost to NJ simply because taxes for travel and leisure are lower. But that is another discussion.

FTRPA is easily one of the prettiest courses/venues in the USA. It's been going strong for MANY years. The first time we (Veronika and I) attended a match there was 2011. MUCH has happened since. Venue though, is still as beautiful as ever.

Between the woods and the lake, scenery is calming and serene.

Range is shared between Airgunners and 3D Archers, and the effort that the Airgunners take to "put the least possible footprint" into the woods is more than commendable:
ALL tree bases get removed after the shoot.
ALL concrete bases and pavers get taken out
ALL stakes/gates also are taken out
NOTHING remains of the shoot

So, EVERYTHING has to be set out again for the next shoot. You will never shoot the same course twice at FTRPA!

HUGE effort, so VERY COMMENDABLE!

THANKS! therefore to the FTRPA crew that spends many hours setting up the field for us to come and shoot!

It is also clear that the Field Target group gets serious support from the Association's Directives. So THANKS also go to them.

The Shoot

At FTRPA, there's a nice sighting-in range, that is also shared with the Archers, so, if you go, do NOT shoot at the foamies! Targets are too big to have any real meaning when shot with a precision airgun at under 55 yards!
The FTRPA crew puts out a more than reasonable sighting in range with targets every 5 yards in plentiful supply.
Also some spinners, some "shoot to reset", and once in a while even some FT's.
Get there early and you will have a ton of fun just shooting at paper.

FTRPA sets out a 60 shot match. They believe this is a good balance between costs (travel, time, money) and enjoyment for other shooters to come and shoot, and they are right, it's a darned good "bang for the buck".

These 60 shots are laid over 10 lanes with 3 targets each lane and two shots per target.
Shoots are not "impossibly hard" usually in the 28 TDR average, in recent times only ONE shooter (and a truly top one at that) has cleaned a Match. So, it takes a LOT of skill and dedication to get high numbers even in a relatively "simple" shoot.

Another aspect that is common at FTRPA is the assistance of new shooters. A lot of it obeys the clear familiarity and friendliness that all the members exhibit, and the atmosphere that prevails and pervades all the shoots. It is an excellent course to get started, and you never stop learning . . . ;-)

One most important part of any shoot is the Shooter's Safety Meeting. Make no mistake, we have shortened the name to SM (Shooter's Meeting) but the real purpose is to re-instill the principles of safe gun handling in all the present shooters, especially the old timers.

Make no mistake (have I emphasized that before?), the first timers are usually VERY aware that they are newbies, it's the "experienced shooters" the ones that need reminding of the safety basics. As in many things in life: "Familiarity breeds contempt", so if you ever need to give one of these, make notes and stick to the notes. Be thorough, be precise, be detailed. The worst series of target failures and cold lines would be a minor imposition/nuisance in the face of an accident.
As a shooter, be aware, be conscious, be courteous, but above all, be SAFE.

Among the WFTF MD's there is the acronym: SFC (no, it does not mean Sargent First Class; it stands for SAFE, Challenging and Fun), which is the aspirational goal of all shoots.

I was paired with Johnathan, a first time shooter, and it was very pleasant to shoot with the young man (I double his age). We proceeded at a good clip and he clearly had done as much of his homework as was possible without actually having gone to a match before.

We started in lane 9:

Here is a zoomed in picture of the targets:

I was fairly confident of my "simple" system (a DIANA 430L shooting H&N "Baracuda FT" pellets: 9.57 grs. / 4.51 mm's at around 734 fps) and proceeded to bring down all targets on both shots.
Apologies that you cannot see how small that long target KZ is. If you locate it on the general picture above, you will only see a black dot where the KZ is and, while I cleaned this lane, the impact on the paddles were all clearly visible, perfect elevation, but to the right.
Hmmmmmm Wind? ... mental note.
John proceeded to shoot his stint and we moved to lane #10:

This was one of the long lanes, I ranged the middle one at 45 yards (41 meters) and the far one at 53 yards (48 meters), and while the near one came down twice, I missed the two shots on the middle one, with impacts clearly one to the right . . . . mental cogs turning . . . and then excessive correction to the left. I hit the long one on the first shot, but under the stress of the SSS (Second Shot Syndrome), missed the second shot.
Here is a zoomed in view:

I decided to adjust my scope 5 clicks to the left before moving to the beginning of the course. John finished and we moved back to Lane 1, but found it busy, and so, I decided to shoot lane 2 and then return to lane 1, this is lane 2:

And here is a detailed look at the long targets:

Before starting to shoot, I took two shots into the ground to settle the scope, since I had clicked 5 clicks between the last lane and this one. It was not a difficult lane at 18 yds (16 m), 22 yds (20 m) and 37 yds (34 m); and all 6 shots found the KZ.
After John took his shots, we moved back to lane 1:

This is another long lane, the near target was already 26 yards (24 meters) away, and from there my rangeings were 35 yds (32 m), and 47 yds (43 m). Here is a detailed view of the long targets:

Of the six shots, I missed the last one. Ah, well . . .
After shooting lane 1, we could advance to lane 3:

And the detailed look:

Got the woodpecker at 20 yds (18 m) twice, then missed second shot at the near squirrel 44 yds (40 m), and missed both shots at the long one 54 yds( 49 m) . And the problem with grey and brown targets is that it is VERY hard to spot your misses.
After John shot we moved to Lane 4:

And this is the detailed view:

Viewed from the standing position, it seems that the short porky is clearly visible, but if you locate the porky in the panoramic picture above, you will see there is a "hump" in the ground that obscures part of the target.
In my, very low, sitting position, the pellet grazed the ground and didn't even touch the faceplate! So that was a miss!
I had to scoot back almost to the limit of holding the muzzle in front of the gate to get the second shot to count.
Distances were not that long: 18 yds (16 m), 27 yds (25 m) and 35 yds (32 m).
After John's turn, we moved to Lane 5 which was the offhand lane:

And here is a detail of the targets:

I ranged 10 yds (9 m), 22 yds (20 m), and 27 yds (25 m), so all were doable, but missed the last two shots.
Arghh . . . need more practice!
After John shot his turn, we moved to lane 6:

With its detailed view:

Dropped all 6 targets. Ranges were not long: 12 yds (11 m), 19yds (17 m), and 22 yds (20 m).
After John shot we moved to Lane 7:

This is John shooting his (very well) home tuned HW97. And here would be a detailed view of the targets:

Got twice the near and mid targets, but the long one eluded me. I suspect that at 49 yds (45 meters), with the sun on my back and a hat made out of rattan that is very airy, but also allows passage of light into the ocular, the budget/simple Diamondback 6-24X50 was having problems giving me the acuity needed to range correctly. I really cannot fault the scope, it is not a "high end scope" and, for the price (under $400), performs admirably. I will have to remember and get some sort of solid hat that precludes the sunshine shining into the ocular, OR an I-cuff or other similar device (but then we start getting away from the "Simple" in the Simple FT concept.

We closed the match at lane 8:

Which was the only lane towards the lake. USUALLY, the wind from the lake plays goofy tricks with the shots, but this time I was lucky and I had some calm.
I had shot the two shots on the first target when John told me:
-There is a person in the lake beyond the middle target, not that you are going to miss, but just to make you aware"
WHAAAT???!!!!
Stood up and tried to locate the person, but he had rowed past, so I deemed safe to shoot again.
I calmed myself down, breathed real deep a few times and asked John which was the next shot.
John informed me that I had to take my first shot on the second target, so I started there and the rest of the shots went well.
Enough to close the Match with a clean lane that is always very nice.

By now, I'm sure some of you are thinking: "How can he remember EVERY shot?"

Truth is: I don't. LOL!

When Veronika started shooting, she made it a point to keep notes of every shot, and so we designed a D.O.P.E. card that I try to keep for all shoots. It is a source of experience, as sometimes after thinking things over a day or two, I come back and find something that needs to be learned.
It is something I would highly recommend:

For example:
Clearly, the long shots are harder than the short ones.
Clearly I have problems with the second shot: 8 of 13 misses were second shots.
Need to work in my offhand shots (usually, real top matches are decided on the "discipline" - forced position - shots).
In this way, you can "coach" yourself to improved scores.

Of course, I always take a picture of the official score card:

And make sure that totals match, LOL!

After all the shooting was done, some of the shooters pitched in to "take out the course":

It's the least we can do to help the FTRPA crew.

After the cleanup, awards were given and conversations got started

After a while, I was reminded that I hadn't brought the wife, LOL!
So I took leave from my friends and started heading home.
The drive home was easier than the one out.
Quick refuel, snack, and in 3 hrs and change I was home.
When you analyze the scores of the match, it becomes clear that the course was not THAT hard (measured as TDR), yet the scores were not THAT high.
There is much more to a course difficulty than the TDR, and even when the MD's think it is one of the easiest they have set, results tell that it was not so easy after all.

As far as equipment is concerned, I am still very happy with my "Simple FT rig" the DIANA 430L is a "good" gun to start with, but with some engineering and the right accessories, it is approaching the "great" status.
The combination of the scope, the mount, the gun, and the pellet has proven that FT'ers should not be afraid of running at slow speeds. It's the accuracy, precision and consistency of a system that are most important.
It is also important to have fun and, if your system is becoming too complicated, take a step back, re-think the whole thing, see into yourself and decide what is what makes you truly happy. Then simplify.
You may loose a few points in the first few matches, but if you were honest with yourself and the simplification gives you more enjoyment, then you will practice more, be more proficient, and in the long run, you will score better.

FTRPA's July shoot is now done, it has become part of the collective memory, some things learned, some things re-learned; it was a hoot and I deeply appreciate Larry's, Rick's, and Jim's knowledge, cooperation and efforts on behalf of the sport.
Good times and good memories are created from this.
AND...
Best thing was to meet old friends and make new ones, I've said it many times, but the best part of FT is the people that shoot FT.

Keep well and shoot straight!

HM

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Shot cycle Dynamics in 3 Spring-Piston Airguns Chap 8

7/22/2021

9 Comments

What happens when you remove the LGU’s muzzle cap?

When first got my LGU, I tried changing as many parameters as possible to see if/how they affected accuracy. First, I tested lots of different pellets. The rifle seemed to like Air Arms Diabolo Field (4.52 mm) pellets, which have tended to be the most accurate pellets in all 12-14 ft-lb rifles that I’ve ever tried. The simplest parameter to change in the rifle itself was to remove the muzzle cap. This greatly increased the report of the rifle, producing a sharp popping sound that is similar to my unmoderated Anschütz 2002 CA PCP air rifle. It also seemed to slightly improve accuracy, so in this chapter I’ll take a closer look at how my LGU performs with and without the muzzle cap/baffle.

Figure 8.1 shows a photo of the LGU’s removed muzzle cap next to the muzzle tube where it was held by a screw. The muzzle cap weighs 36 g (1.3 oz). Since I’m using a computer hard drive magnet to hold the end of the cocking lever in place, I also removed the cocking lever latch. For more info on these mods, please see:

https://www.gatewaytoairguns.org/GTA/index.php?topic=168525.0

Fig. 8.1 Photo of the LGU’s muzzle cap (on left) next to the muzzle tube where it was held by a screw.

Figure 8.2 shows 5-shot groups shot off the bench at 20 yards with the muzzle cap (top six targets on left card) and without muzzle cap (bottom two targets on left card and all targets on right card). Two out of the six groups with the muzzle cap showed significant vertical stringing (see red ovals). The groups without the muzzle cap tended to be rounder. The mainspring used here was a shortened Maccari (moderate FAC, 30 coils x .125 wire) that was shooting around 11 ft-lb. This was only preliminary evidence that the muzzle cap was affecting accuracy.

Fig. 8.2 5-shot groups at 20 yards off the bench for LGU with and without muzzle cap on 8/14/19 using shortened Maccari mainspring shooting around 11 ft-lb.

In January 2020 I installed a 16 J factory mainspring that was shooting around 12 ft-lb. Figure 8.3 shows more 5-shot groups with and without the muzzle cap. The left target card was shot with the muzzle cap in place and the right two cards were shot without the muzzle cap. Most of the groups on the left card looked pretty good, but about a third of them, circled in red, showed the vertical stringing that I observed before. Two things happened when the muzzle cap was removed, as can be seen in the right two cards in Fig. 8.3. First, the POI shifted down and slightly to the left. Second, the groups were rounder with less tendency to string vertically. If anything, there may have been some horizontal stringing going on (see groups circled in green) when the muzzle cap was removed!

Fig. 8.3 5-shot groups at 20 yards off the bench for LGU with and without muzzle cap on 1/20/20 using factory 16 J spring shooting around 12 ft-lb.

Further qualitative accuracy comparisons can be found in Fig. 8.4, where five 5-shot groups were made without the muzzle cap, followed by four 5-shot groups with the muzzle cap, and finally by a single 5-shout group without the muzzle cap. I used the term “muzzle brake” instead of muzzle cap when I annotated the targets. I overlayed the groups on the right side of the target card and found that the 20-shot composite group without the muzzle cap was significantly smaller and rounder than the 20-shot composite group with the muzzle cap, which again tended to be stringing vertically. Even the 30-shot composite group without the muzzle cap looked better than the 20-shot composite group with the muzzle cap.

Fig. 8.4 5-shot groups at 20 yards off the bench for LGU with and without muzzle cap 1/28/20 using factory 16 J spring.

In Fig. 8.5 I try to quantify the accuracy differences better. On the left card in Fig. 8.5, I shot four 5-shot groups, five 10-shot groups, and a 20-shot group, all with the muzzle cap attached. The bottom four 10-shot groups on the left card were made with the muzzle cap removed. On the right card, the top eight 5-shot groups were made with the muzzle cap removed, followed by eight 5-shot groups with the muzzle cap attached, and finally two 5-shot groups with no muzzle cap. I alternated groups with and without the muzzle cap to reduce any artifacts due to accuracy drifting with time. Again, groups without the muzzle cap tended to be smaller and rounder, with a lower POI than groups with the muzzle cap.

Fig. 8.5 5-, 10-, and 20-shot groups at 20 yards off the bench for LGU with and without muzzle cap on 4/9/20 and 4/12/20 using factory 16 J spring.

Figure 8.6 summarizes the accuracy test made in Fig. 8.5. The ctc distances for the 5-, 10-, and 20-shots groups shot with the muzzle cap were at least 20% larger than the groups shot without the muzzle cap. The difference became more significant as more shots were included in the groups, since the vertical stringing by the muzzle cap was intermittent and one could still get some pretty nice 5-shot groups with the muzzle cap attached. However, if one shot more groups or put more shots into a group, the stringing tendencies of the muzzle cap started to become more apparent.

Fig. 8.6 Average ctc group size at 20 yards off the bench for LGU with and without muzzle cap.

Finally, I wanted to check if the accuracy differences would show up in recoil traces. Figure 8.7 shows the rifle’s velocity as a function of time for three shots with the muzzle cap and three shots without the muzzle cap. They all look the same to me! I think this confirms Hector’s diagnosis that the vertical stringing is due to barrel harmonics, which wouldn’t show up in the overall rearward motion of the rifle. If one could zoom in on the muzzle in time and space, one would see that it’s swinging around like the end of a diving board.
During the middle of the swing, the barrel muzzle is moving the fastest and its direction is changing the most. Therefore, if the pellet leaves the barrel when the muzzle is in the middle of its swing, small changes in the pellet exit time and/or the barrel vibration will cause pellet POI to be more spread out laterally. On the other hand, if the pellet leaves the barrel when the muzzle is at the end of its swing, and therefore stopped and is about to turn around to head back in the opposite direction, there will be much less variation in the muzzle orientation and accuracy will be much better.
Removing the weight of the muzzle cap changes the barrel harmonics towards the more favorable situation where the pellet leaves at the end of the muzzle swing. Recent measurements have shown that this is the case. Using a DIY angle-o-meter, I found that with the muzzle brake attached, the pellet leaves the muzzle when the barrel is swinging down, near the middle of its swing. Without the muzzle brake, the barrel oscillations are faster and the pellet leaves near the bottom of the muzzle swing, causing the POI to be lower and the vertical dispersion to be less, since the muzzle is stopped at the bottom of the swing when the pellet exits. For more details on this, please see my post in Shooting the Breeze:

https://shooting-the-breeze.com/threads/barrel-vibration-measurements-in-my-lgu.52757/

Fig. 8.7 Three velocity recoil traces without the muzzle cap (blue) and three recoil traces with the muzzle cap (orange) from my LGU.

The main lesson that I got out of this is that although manufacturers have good reasons for adding every part on their air rifles, sometimes these parts do more harm than good, depending on one’s priorities. I’m happy to live with a louder LGU if it means that is shoots more accurately. I’m very curious to hear if any readers have noticed a difference. Have you tried removing the muzzle cap on your spring piston air rifle? It may be worth a try!

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Hector Medina

2012 US National WFTF Spring Piston Champion
2012 WFTF Spring Piston Grand Prix Winner
2013 World's WFTF Spring Piston 7th place
2014 Texas State WFTF Piston Champion
2014 World's WFTF Spring Piston 5th place.
2015 Maine State Champion WFTF Piston
2015 Massachusetts State Champion WFTF Piston
2015 New York State Champion WFTF Piston
2015 US National WFTF Piston 2nd Place
2016 Canadian WFTF Piston Champion
2016 Pyramyd Air Cup WFTF Piston 1st Place
2017 US Nationals Open Piston 3rd Place
2018 WFTC's Member of Team USA Champion Springers
2018 WFTC's 4th place Veteran Springer
2020 Puerto Rico GP Piston First Place
2020 NC State Championships 1st Place Piston

Hector's Airgun Blog

The Super-Plinker/Best of both worlds.- DIANA 280

Shot cycle Dynamics in 3 Spring-Piston Airguns Chap 9 NEW-NEW

Conclusions: What does all this means?

So here are the conclusions, finally!

Nur für Jäger / Only for hunters.- Take TWO

Simple Field Target #3.- FTRPA July 18th 2021

Preamble and Acknowledgements

The Shoot

Shot cycle Dynamics in 3 Spring-Piston Airguns Chap 8

What happens when you remove the LGU’s muzzle cap?

Hector Medina

Archives

Categories

Hector's Airgun Blog

The Super-Plinker/Best of both worlds.- DIANA 280

Shot cycle Dynamics in 3 Spring-Piston Airguns Chap 9 NEW-NEW

Conclusions: What does all this means?

So here are the conclusions, finally!

Nur für Jäger / Only for hunters.- Take TWO

Simple Field Target #3.- FTRPA July 18th 2021

Preamble and Acknowledgements

The Shoot

Shot cycle Dynamics in 3 Spring-Piston Airguns Chap 8

​What happens when you remove the LGU’s muzzle cap?

Hector Medina

Archives

Categories

What happens when you remove the LGU’s muzzle cap?