About a year ago (Dec. 3, 2014 to be exact), I posted the first entry about the Walther "Sport" family of guns..

It took me a year to get back to these fine guns by request of a good friend of mine.

In the interim, we had imported the 12 ft-lbs kits directly from Germany, and results had been good with the LGU. But this friend wanted to have a "Matching Pair" of sub-12 Ft-Lbs guns. One built on an LGV, one on the LGU.

And so started our Odyssey.

I have posted enough info on tuning the LGU before, but I will try to outline those things that are different and important with the LGV.

We start with a run of the mill 12 ft-lbs kit from Walther and the corresponding adjustable trigger:

Careful measurement of all the components told us that we WOULD have to change the guide (the LGV guide is slightly thick for the 12 ft-lbs spring). And given the fact that the pistons weigh the same and we had no way (no SENSIBLE way, that is) of modifying the transfer port, we knew there would be problems, but a fore-warned ambush should kill no soldiers, so we forged head with some plans in mind.
There is no way of testing the accuracy of a gun without a proper sighting system, so a UTG drooped rail was machined to fit:

An RWS 3-12X50 scope we routinely use for tests was installed and we now could do some testing.
At 10 meters and full power, the gun was not keeping 10 shots inside the 6 meter chicken (rightmost group):

And we sort of expected that. The JSB's are not often the preferred pellet of the Walthers.
We sifted through our correspondence and found a cryptical allusion to a 'Hatsan Air Stripper' in one of my good friend Mark Bouchard's Emails.
And so I installed one of those "muzzle brakes"  and proceeded to tune the center cone for the best possible group.
You can see how the group tightened from right to left.
After I was done, the gun was keeping all shots to the chicken's head. Not bad for factory part that was not even produced by the rifle maker! Thanks Mark!
And then we proceeded with the power conversion.
The pistons were extracted and compared:

On top, the FP piston, on the bottom, the 12 ft-lbs one.

Essentially, both pistons are identical in all aspects, EXCEPT construction. The 'new' pistons are a simplified construction version of the originals. Looking at the silver lining, our worries about the transfer port were abated a little.

Then we measured and compared the springs:

On the top, the 12 ft-lbs spring, on the bottom, the FP one. Do note the plastic TopHat.
There seemed to be little difference between one and the other. Not enough to make it develop 1.5 ft-lbs less.
Still, we decided to test the spring as it was delivered by Walther.
And sure enough we found a few things we did not like:
Power was high, about 13 ft-lbs which would make this illegal for FT, and the usual piston bounce-back and vibrations were there.
With the experience of the prior LGU tunes, we decided to cut off one full coil of the spring and install a composite TopHat that fit VERY tightly in the piston:

It is important to note that to make the spring "grab" the TopHat, the diameter of the foremost 2 turns had to be reduced. So, to preserve that, the cutting of the spring took place at the REAR.
When cutting a spring, you need to forge and square the ends, otherwise ALL springs will kink and start giving problems. So, we forged and squared the spring's rear end.
Of course, this required the performance of the "stand-up" test.

An airgun mainspring must ALWAYS be straight and square enough to stand up straight on its own. If it is not, then use a wheel, or re-forge the end. No sense in putting extra work on the guide by starting with a cocked up spring's rear end.
A note here to support the use of the OEM greases. Walther provides two different greases: A larger jar of 'Piston Grease' (KolbenFett), and a smaller jar of 'Spring Grease' (FederFett):

Both greases are notably temperature stable and the flash point of both is extremely high.
The proportion tells you that Walther EXPECTS you to use 3 times more grease for the piston than for the spring. IF (BIG IF) the springs last about 15,000 rounds, then that means that you are expected to break open and make sure your piston is well lubricated every 5,000 rounds.
Maybe I should start working on an ORing'ed piston for these guns, but we'll se how it goes; for most people, 5,000 rounds is about a year's worth of shooting. So an ORing piston may not be completely warranted.

Gone are now the piston bounce and the vibrations of a loose system. The gun is consistent and uniform in all its behaviors, a definitely likable airgun.

After the trigger swap, the gun is now shooting reasonably well and as soon as possible, we'll be testing it at distance.

If the short range groups hold, it will, indeed, be a sweet shooter!

If I could have a Christmas wish granted, all shooters would heed Walther's admonition:

ROFL!

Keep well, shoot straight, and Merry Christmas to ALL!






HM

I received a request from a very good friend to publish in this space the main differences between the FT scopes made by Sightron.
Sightron is one of the few companies that sets out in very clear terms what the specifications for each scope are, but I understand that some specialized terms and maths may need some further clarification, so let's see them side by side:

On the left you can see the specs for the Mil Hash scope , on the right you see the spec for the MOA scope. As you go down row by row, you see that the first difference is the reticle type. Up until that point, both scopes were identical.
BOTH scopes are "true" to the units their reticle is designed at 24X, and our analysis will be done at that magnification. Because BOTH scopes are Second Focal Plane (SFP), it is important to compare them at the same magnification.
The Mil-Hash scope has a click value of 0.05 mrads and the MOA scope has a click value of 1/8 MOA, so, how can we compare one and the other?
Remember that a milrad is 3.438 MOA's, so 0.05 mrads= 0.172 MOA's, while 1/8 MOA is 0.125 MOA
In essence, 1/20 mrad (or 0.05 mrad) is ABOUT 1/6th of an MOA, which is 37½% LARGER than 1/8 MOA

Some shooters think that they NEED the finest possible division of the complete turn to sight-in their rigs, but the reality is that in FT that is not so important:
1/8 MOA at 55 yards is 0.072" =((1.047" x 0.55)/8), or in other words, one click is less than one half a pellet diameter.
1/20 mrads at 55 yards is 0.099", or in other words, one click is a little more than one half a pellet diameter.

Not even the best target paper will resolve these differences, it will be one slightly enlarged hole. The slightest wind, the slightest difference in the pellets will present a much larger deviation.
To be perfectly clear: the current state of the art in pellets, rifles, barrels and shooters could not detect these differences. Many real good shooters shoot fantastic scores using scopes with ¼ MOA clicks (about a 0.177" pellet diameter at 55 yards).

Now, If each click is larger, does this mean that one turn will have a larger excursion?
Not necessarily.

Coming back to our scopes, we see that the Mil Hash scope has a total excursion of 2.5 mrads/rev. The MOA scope has 10 MOA's /rev. so, converting both to MOA, we get that the Mil Hash scope has a revolution with an excursion of 8.6 MOA's (= 2.5 x 3.438), while the MOA scope has a full 10 MOA's in a revolution.
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This is one case where the finer division ALSO entails a larger excursion in the elevation of one revolution.
For those that click the elevation for each shot, and shoot under WFTF rules (12 ft-lbs maximum muzzle energy), it means that the MOA scope MAY accommodate their full trajectory from 9 to 55 yards in one revolution, but for the same trajectory, the Mil-Hash scope may not.

Does this mean that one scope is superior to the other? not necessarily, it all depends on how YOU shoot. YOUR habits, wants and needs.

Once you move past that point, the rest of the specs tell you that the scopes are almost identical with the exception being that the MOA scopes have caps that protect the turrets, while the Mil Hash scopes have open turrets.

Now, for those shooters that do NOT CLICK, OR for those that use the reticle to hold off for wind; understanding the reticle is vital.

Let's see the two reticles side by side:

Again, on the left is the Mil-Hash scope, on the right is the MOA scope.
The TOTAL side to side subtension of the whole reticles is marked in the diagrams as dimension "A".
For the case of the Mil Hash scope "A" is 10 milrads at 24X, for the MOA scope dimension "A" is 20 MOA's.
Converting the milrads to MOA, we get that the Mil-Hash scopes have a total subtension of 34.38 MOA's, while the MOA scopes have "only" 20.
The REAL problem for FT shooters comes not at 24X, because 20 MOA's of wind is quite a lot, BUT if shooters drive their scopes to 50X for ranging AND for shooting, then having 9.6 MOA's (=20 x 24/50) MAY not be enough.

Here again, the specific shooter wants and needs and habits creates a substantial difference between shooters using IDENTICAL EQUIPMENT.

Shooters that shoot at AROUND 33X +/- 3X (that means from 30 to 36X) will generally be able to use all the advantages of the MOA scopes, but shooters that shoot at 50X will NEED the Mil-Hash for holding into the wind, and that MAY entail having to use MORE than one revolution to accommodate ALL the trajectory.

Personally, I use my FT MOA-H scope (different reticle, but all the maths hold the same) at 29X, which is the magnification at which the "2 MOA" divisions actually become ½ mrads in reality. This allows me to check my ranging using stadia-ranging (or miling, or bracketing, same thing different name). And helps me in using my ballistics app (PP-Calc) with confidence.

Here is the lit MOA-H reticle in a Hector's Special Sightron 10-50X60 FT scope:

As you can see, with this reticle I can hold off PRECISELY for elevation and windage using ONLY the reticle. Once the gun is zeroed, my only concerns are to range well and consult my tablet.

Hope this has made clear to most what are the real differences between the two models. EACH shooter must decide for himself what he can use best.
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Good luck, keep well and shoot straight!






​Héctor Medina