Using a 34k in 0.20" cal
The EMS powerplant is a peculiar beast.
The result of extensive tests (thousands and thousands of shots taken), and the desire to make a dual power-plant rifle, it is a 7 part system (L to R in the picture below):
Piston
Forward guide
Spring
Shim
Rear guide
Piston skirt centering bell
Filler Screw
The result of extensive tests (thousands and thousands of shots taken), and the desire to make a dual power-plant rifle, it is a 7 part system (L to R in the picture below):
Piston
Forward guide
Spring
Shim
Rear guide
Piston skirt centering bell
Filler Screw
Now, being a 7 part system means TWO things:
1.- More manufacturing cost
2.- The need for more precision in the execution
For three years now, the "Motto" of the DIANA brand has been:
"Our Mission is Precision"
AND, as it is basically unavoidable, like all changes, it needs to start from within (remember the song "The Man in Mirror"?)
So, this exploration goes into what can be GAINED by using a steel spring in the D-34 sized break-barrels with the EMS architecture, and what needs to be changed.
Let's start with the diagram:
1.- More manufacturing cost
2.- The need for more precision in the execution
For three years now, the "Motto" of the DIANA brand has been:
"Our Mission is Precision"
AND, as it is basically unavoidable, like all changes, it needs to start from within (remember the song "The Man in Mirror"?)
So, this exploration goes into what can be GAINED by using a steel spring in the D-34 sized break-barrels with the EMS architecture, and what needs to be changed.
Let's start with the diagram:
Numbers 1, 2, 3, and 4 are the basic mechanisms tube with the trigger block included.
Number 5 is the rear spring guide
Number 6 is a steel centering "bell" designed to hold the piston in the center when cocked, and allow the interference sear to do its job consistently.
Number 7 is a washer to protect the plastic rear guide from the steel spring
Number 8 is the screw that affixes the centering bell (# 6) to the trigger block (#2).
Number 9 is the spring itself
Number 10 is the front guide that telescopes into the rear guide
and Number 11 is the piston
Now, let us think about DIANA's "motto":
We have 7 pieces that need to align along an axis that is about a foot long (12"~~ 300 mm) and upon whose precision depends the consistency and efficiency of the powerplant.
¿Why?
Well, in a spring-piston powerplant there are several energy "sinkholes". The most important is friction, we take care of that mostly through lubrication. The next one in importance is "chatter", and that means all the small lateral movements that happen when a long thing vibrates along an expansion stroke.
How important is chatter?
Well, let's just say that IN THE SAME rifle-pellet-lubricant combination, a traditional D34 powerplant was able to yield about 13½ ft-lbs
Then, with the NTec unit (that prevented a lot of the chatter), yield went up to 16 ft-lbs.
With a "precisioneered" (precision engineered) EMS architecture it is now yielding 17 to 17½ ft-lbs
AND with a reduced cocking effort because Gas Springs will ALWAYS start from a very high force and go higher from there.
So, by reducing the tolerances and ensuring that everything is operating along the same axis, we gained a bit more than 25% yield with a reduction of about 20% in the cocking effort (and therefore the energy input into the system).
Yup! That is what true precision gains for us.
If you put it in numbers:
Efficiency of a traditional 34 PP.-
13.6 kg (30 #F, or 133.4 N) PCF over 135° of arc (2.36 Rads) on a 0.34 m radius.- Since the Compression starts from a value (preload), we will take that into account by an arbitrary/empirical factor of 0.6 (the average is a little more than ½ the peak) That means 64.22 Joules of energy input, vs. 17.6 J output, means an efficiency of about 27%
Efficiency of an Ntec equipped version:
20 kg (44 #F, or 196.2 N) PCF over the same arc and radius, means a peak input of 157 J, since the NTec starts from a substantially higher force, the factor now for the average force is about 0.7, instead of 0.6, so the input is 110.2 J, for an output of 21.7 J, that means an efficiency of 20%
Efficiency of the steel spring'ed EMS PP.- you need to input 18.2 kg (40 #F or 178.2 N)since this PP starts from a low value, we use again the 0.6 factor for the average vs the peak, and that means an input of 85.8 J, for an output of 24 J means an efficiency of 28%
Is this performance max'ed out for the 34 size? Yes. To get more/more efficiency, we would need to go the route of the fixed barrels.
Now, is there a way to achieve these gains without increasing the cost?
Well, yes, but it needs a change of thinking.
On one hand, parts #'s 5, 6, 7 and 8 can be "unitized" in a single piece made up with two different materials in three parts.
Could it be made as a single extrusion/molding? Perhaps. Modern moulding techniques do allow for "overmoulding", meaning that you mould a part, then insert that into another mould and the final injection takes place.
But what is a dramatic departure from the traditional method of manufacturing is that this "unitized" part would have to be made OVERSIZE, and then CNC machined to precise dimensions with small tolerances.
The frontal guide (#10) also needs a serious tightening of tolerances, especially at the front where it meets the piston. AND the fit between the OD of the "stem" of part #10 and the ID of the "Unitized" guide also needs serious tightening, as well as the fit between spring and guide.
I am now hearing all of you saying:"Precision in manufacturing is not the same as precision at the target
LOL!
Yes, that is true, and not only precision, but accuracy is also important. Theoreticians think that if you achieve precision, then accuracy is the "simple matter of adjusting the sights".
Alas, those shooters with experience know that this is an oversimplification.
What happens if the sights don't adjust consistently?
What happens if the sights are vulnerable to thermal differences?
What happens if the sights are simply not adequate to the target at hand?
Many of the problems are "solved" using a scope, but scopes have their own issues, especially in the field.
Still, the best procedure to test a rifle is by shooting it.
And, yes we did a ton of that, mainly because our scope suddenly started playing scope "games" on us. We would shoot a great group at some point in the target, then the next group would be elsewhere. The we shot a shotgun pattern that was not even a group!
Since that particular scope has been with me for a LONG time and never failed, AND that scope has been mounted in "accurized" ZR Mounts, that is the last point we suspected.
So, we tuned the bedding (after all, even the most "sophisticated 34 is still a 34.We tuned the Muzzle piece (an HPM Unit), and we tested different pellets.
The pellets were not the issue, the JSB's 13.7's were shooting as they should.
The bedding took a bit of experimenting, at this power level, minute differences have substantial effects.
After three days of testing (and two full pages like this), we decided something was wrong, this is what we were getting:
Number 5 is the rear spring guide
Number 6 is a steel centering "bell" designed to hold the piston in the center when cocked, and allow the interference sear to do its job consistently.
Number 7 is a washer to protect the plastic rear guide from the steel spring
Number 8 is the screw that affixes the centering bell (# 6) to the trigger block (#2).
Number 9 is the spring itself
Number 10 is the front guide that telescopes into the rear guide
and Number 11 is the piston
Now, let us think about DIANA's "motto":
We have 7 pieces that need to align along an axis that is about a foot long (12"~~ 300 mm) and upon whose precision depends the consistency and efficiency of the powerplant.
¿Why?
Well, in a spring-piston powerplant there are several energy "sinkholes". The most important is friction, we take care of that mostly through lubrication. The next one in importance is "chatter", and that means all the small lateral movements that happen when a long thing vibrates along an expansion stroke.
How important is chatter?
Well, let's just say that IN THE SAME rifle-pellet-lubricant combination, a traditional D34 powerplant was able to yield about 13½ ft-lbs
Then, with the NTec unit (that prevented a lot of the chatter), yield went up to 16 ft-lbs.
With a "precisioneered" (precision engineered) EMS architecture it is now yielding 17 to 17½ ft-lbs
AND with a reduced cocking effort because Gas Springs will ALWAYS start from a very high force and go higher from there.
So, by reducing the tolerances and ensuring that everything is operating along the same axis, we gained a bit more than 25% yield with a reduction of about 20% in the cocking effort (and therefore the energy input into the system).
Yup! That is what true precision gains for us.
If you put it in numbers:
Efficiency of a traditional 34 PP.-
13.6 kg (30 #F, or 133.4 N) PCF over 135° of arc (2.36 Rads) on a 0.34 m radius.- Since the Compression starts from a value (preload), we will take that into account by an arbitrary/empirical factor of 0.6 (the average is a little more than ½ the peak) That means 64.22 Joules of energy input, vs. 17.6 J output, means an efficiency of about 27%
Efficiency of an Ntec equipped version:
20 kg (44 #F, or 196.2 N) PCF over the same arc and radius, means a peak input of 157 J, since the NTec starts from a substantially higher force, the factor now for the average force is about 0.7, instead of 0.6, so the input is 110.2 J, for an output of 21.7 J, that means an efficiency of 20%
Efficiency of the steel spring'ed EMS PP.- you need to input 18.2 kg (40 #F or 178.2 N)since this PP starts from a low value, we use again the 0.6 factor for the average vs the peak, and that means an input of 85.8 J, for an output of 24 J means an efficiency of 28%
Is this performance max'ed out for the 34 size? Yes. To get more/more efficiency, we would need to go the route of the fixed barrels.
Now, is there a way to achieve these gains without increasing the cost?
Well, yes, but it needs a change of thinking.
On one hand, parts #'s 5, 6, 7 and 8 can be "unitized" in a single piece made up with two different materials in three parts.
Could it be made as a single extrusion/molding? Perhaps. Modern moulding techniques do allow for "overmoulding", meaning that you mould a part, then insert that into another mould and the final injection takes place.
But what is a dramatic departure from the traditional method of manufacturing is that this "unitized" part would have to be made OVERSIZE, and then CNC machined to precise dimensions with small tolerances.
The frontal guide (#10) also needs a serious tightening of tolerances, especially at the front where it meets the piston. AND the fit between the OD of the "stem" of part #10 and the ID of the "Unitized" guide also needs serious tightening, as well as the fit between spring and guide.
I am now hearing all of you saying:"Precision in manufacturing is not the same as precision at the target
LOL!
Yes, that is true, and not only precision, but accuracy is also important. Theoreticians think that if you achieve precision, then accuracy is the "simple matter of adjusting the sights".
Alas, those shooters with experience know that this is an oversimplification.
What happens if the sights don't adjust consistently?
What happens if the sights are vulnerable to thermal differences?
What happens if the sights are simply not adequate to the target at hand?
Many of the problems are "solved" using a scope, but scopes have their own issues, especially in the field.
Still, the best procedure to test a rifle is by shooting it.
And, yes we did a ton of that, mainly because our scope suddenly started playing scope "games" on us. We would shoot a great group at some point in the target, then the next group would be elsewhere. The we shot a shotgun pattern that was not even a group!
Since that particular scope has been with me for a LONG time and never failed, AND that scope has been mounted in "accurized" ZR Mounts, that is the last point we suspected.
So, we tuned the bedding (after all, even the most "sophisticated 34 is still a 34.We tuned the Muzzle piece (an HPM Unit), and we tested different pellets.
The pellets were not the issue, the JSB's 13.7's were shooting as they should.
The bedding took a bit of experimenting, at this power level, minute differences have substantial effects.
After three days of testing (and two full pages like this), we decided something was wrong, this is what we were getting:
Yes there were some great groups, but... no consistency.
This is a good example:
This is a good example:
Five shots vertically scattered, then a tight group, then another five horizontally scattered.
Now look at this:
Now look at this:
Top row left to right:
A so-so group, then a better group, then a hideous group, then another good group with a lonely "flyer".
AND, we knew that it was not a question of oscillating MV's:
A so-so group, then a better group, then a hideous group, then another good group with a lonely "flyer".
AND, we knew that it was not a question of oscillating MV's:
So, we decided to swap scopes.
Wonder of wonders, miracle of miracles! LOL!
This is what we got, straight off the bat:
Wonder of wonders, miracle of miracles! LOL!
This is what we got, straight off the bat:
This is the process of sighting in.
And when you click an inexpensive scope, you EXPECT to have to take one or two shots to settle it down.
Even some not so inexpensive scopes do this. Especially in a springer that is yielding almost twice its own weight in output energy.
At 25 yards, these are dime-sized groups from the knee and a scope @ 9X, let's validate that assertion:
And when you click an inexpensive scope, you EXPECT to have to take one or two shots to settle it down.
Even some not so inexpensive scopes do this. Especially in a springer that is yielding almost twice its own weight in output energy.
At 25 yards, these are dime-sized groups from the knee and a scope @ 9X, let's validate that assertion:
Yes, I know there is one Canadian dime there, What do you want? I like the guys!
Want to see how the groups are totally covered?
Want to see how the groups are totally covered?
I need to finish the sighting in, but that will come at a later date when there is less wind.
Is it easy to shoot a light and powerful break barrel? Nope!
It would make a heck of a hunting rifle, or perhaps Silhouette?. Short, light (9# WITH scope), and with a lot of KO power as far as pigeons, squirrels, grackles , rats, etc. are concerned.
So, there you have it. Power, precision and accuracy in one small, light package.
AH! before I forget, dry lubed. Absolutely no oils or greases in the compression section.
In short, precision at the target comes from "internal harmony", and "internal harmony" comes from the precision fit between the parts that make up the heart and soul of the airgun.
Same could be said of humans ¿no?
Keep well and shoot straight!
HM
Is it easy to shoot a light and powerful break barrel? Nope!
It would make a heck of a hunting rifle, or perhaps Silhouette?. Short, light (9# WITH scope), and with a lot of KO power as far as pigeons, squirrels, grackles , rats, etc. are concerned.
So, there you have it. Power, precision and accuracy in one small, light package.
AH! before I forget, dry lubed. Absolutely no oils or greases in the compression section.
In short, precision at the target comes from "internal harmony", and "internal harmony" comes from the precision fit between the parts that make up the heart and soul of the airgun.
Same could be said of humans ¿no?
Keep well and shoot straight!
HM
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