by Tom Gaylord
Writing as B.B. Pelletier
The AirForce Edge target rifle.
This report covers:
- How to begin?
- Jump in
- Edge reports
- THIS Edge
- Off the reg.
How to begin?
Remember me telling you I had a backlog of reports to do? This rifle that I got from reader RidgeRunner is one of them. But I need to change my report format this time because I need the AirForce Edge target rifle for another test I’m doing — the report on testing the H&N Baracuda FT pellet.
I wanted to test that pellet with an accurate precharged rifle as well as several spring piston guns, and this Edge is my most accurate PCP in .177 caliber. It’s also more powerful than a standard Edge target rifle. RidgeRunner modified this Edge by adding a firing chamber to boost the power to almost double that of a conventional Edge. A firing chamber collects and holds the compressed air that has passed through the regulator, so more air is available for the shot. Nothing has to be done to the regulator when a larger chamber is used. It simply provides more air to push the pellet — a bigger or longer push, if you will.
You don’t get the silver part arrows) with a standard Edge. That’s where the firing chamber lives.
The rifle is still less than 12 foot-pounds, so it isn’t out of control, but this Edge is the perfect testbed for the new H&N pellet. RidgeRunner told me if I were to install an 18-inch barrel on the gun it would get nearly 12 foot-pounds. However, I left the 12-inch barrel on the gun, so that’s what we are testing today.
But this is also an Edge target rifle and it deserves a report of its own! See my problem? Do I start at the beginning or jump right in as if everyone knows what an Edge is and what it can do?
I’ve decided to jump right into the middle and start with a report on this rifle as it has been modified. That way I can get it into the pellet test in the next report. But I will come back and cover the history of the rifle, its development that I was pleased to watch, as well as it’s impact upon the world of junior marksmanship competition. And I will test it as an Edge.
I need to leave myself a reminder of what I have promised to report on later, so here is a synopsis. The Edge is one of two rifles that were created for the NRA Junior Marksmanship program. It was started by a chance presentation at the SHOT Show, where the NRA told the airgunning world that over a million junior shooters compete each year in a multi-tiered competition that involves over 74,000 different teams around the nation.
The Edge was three years in development, during the time that the NRA and CMP refined their “specifications” for a junior marksmanship target rifle. Each person involved in the process of opening the competition to airguns other than Daisys was able to say, “No” but nobody wanted to say, “Yes” to what a junior marksmanship rifle had to be. For several years it seemed like Spanky and Our Gang had been asked to produce a Broadway show!
The Edge is the most ergonomic 10-meter junior rifle ever created. That fact turns off some shooters, though they are presented with boatloads of possibilities for personalization and fit. It has a trigger that was designed for dry-firing, and its American-made sights are the only target sights currently being produced in this country. There is a big story to tell, but for now I must move on.
The Edge trigger is designed for dry-fire. This makes it ideal for training.
The graphics above the bolt show the user how to operate the bolt for dry-fire.
I wrote a 7-part report on the Edge back in 2009 and 2010. You can look at those articles to get the background of the rifle, plus look at the testing I did at that time. But I will test the Edge all over again with this rifle.
That brief history and link to those old reports will prompt me to go back and cover the rifle from the beginning, but now let’s look at this particular rifle. RidgeRunner wanted an Edge his way, so he added a firing chamber that boosted the power and reduced the shot count from about 110 to 25. I will actually test the shot count for you today.
While this is a standard Edge in most respects, and, while all the modifications can be reversed, which I plan to do, right now this rifle has something I want — more power! That will let me test the Baracuda FT pellet the way it is intended to be used.
It also has a superb trigger that has been modified by RidgeRunner by the exchanging of springs in the trigger mechanism. As you may know, the pull weights of 10-meter rifle triggers are not regulated, except in the Junior class. There they must break with no less than 1.5 lbs./680.4 grams of pressure. Well, RidgeRunner wasn’t going to compete in anything, so he made this trigger his own. It’s a two-stage pull with an exceedingly short and light first stage that stops at 0.7 oz. Stage two breaks at one pound, even — every time. An adult 10-meter rifle shooter who is used to a 50-gram/1.76-oz. trigger pull will notice the difference, but the average airgunner will fire this gun before he or she is ready.
To test the velocity I shot a string of RWS Meisterkugeln Rifle pellets. RidgeRunner had told me the rifle was capable of producing nearly 12 foot-pounds with an 18-inch barrel, so I guesstimated that with the original 12-inch barrel it would push the 8.2-grain Meisterkugelns out at around 700 f.p.s. or slightly more. Let’s see.
13……………..not recorded (very slow)
17……………..not recorded (very slow)
27……………..699 — off the reg.
** the actual recorded velocity.
When shot 6 came out at 267 f.p.s. I thought maybe a heavier pellet had gotten mixed in the tin, but in reality no pellet would ever be that slow in the middle of a 700+ f.p.s. string, regardless of the weight. I recorded it and continued shooting.
Shot 13 came out so slow that I barely heard it, and the chronograph didn’t record it. I had to check the barrel to make sure it came out. The same for shot 17. What’s happening? Remember when I told you that it isn’t a matter of if a regulator fail but when? I think we might be seeing the first sign. If RidgeRunner didn’t adjust the reg. for his modifications, and he didn’t, then it isn’t under any additional stress, even though the gun shoots harder because of the large firing chamber. It could be starting to fail just from the from time it’s been in service.
Another possibility is that the gun hasn’t been shot enough recently and the reg. is just stiff from sitting around. With time and more shooting it may loosen up and start functioning again.
I didn’t provide an average for this string, but if we take 715 f.p.s. as an average velocity, the Meisterkugeln develops 9.31 foot-pounds at the muzzle. That’s with a 12-inch barrel. A 9.6-grain H&N Baracuda moves out at 685 f.p.s. and develops 10 foot pounds, exactly. When I get to the pellet test, that’s the energy I will be reporting.
Off the reg.
RidgeRunner told me to expect 25 shots and that’s what it was, more or less. It is very clear that the rifle “fell off the reg.” on shot 27. From that point on you can expect to see a linear drop in velocity for any pellet you are testing. The regulator is no longer working because the pressure remaining in the reservoir is lower than the pressure needed to make the regulator to do its job. The reg is open and is just a straight-through air passageway now.
My plan is to mount a scope on this Edge next, so I can use it to test the Baracuda FT pellets. Then I will remove the scope, the firing chamber, mount the target sights and return the rifle to its normal operation, which would be a 7.56-grain H&&N Finale Match Pistol pellet moving around 520 f.p.s. At that speed the rifle gets over 100 shots per 3,000 psi fill of its very small air reservoir.
In that configuration I will test this Edge as a 10-meter target rifle, giving you full details of the design and operation. I plan to contact AirForce Airguns to learn if there have been any changes to the Edge over the years. This is a very early rifle with the serial number of 10. If there have been changes I will report them, as well.
The AirForce Edge target rifle is a remarkable product that’s full of innovation and performance. I hope to present as much of that as I can in this series.
65 thoughts on “AirForce Edge 10-meter rifle: Part 1”
I’ve liked the airforce guns for over a decade now. But the lack of a regulator has stopped me from buying one recently. Are there good aftermarket one’s?
Indeed there are. Search for JDSAirman. He has all kinds and sizes of regs for these. If you dig around you can find others.
That’s the ticket!
I live my edge, they are regulated. For its intended purpose, I don’t think there is a finer American made .177 rifle out there, and as shown here, the modifications are endless. With a good scope and the right pellet, it will hit anything you want as small as you can see at 25 yards and less.
Empty .22LR hulls, no problem, shoot the staples out of your friends target on the next target board? No problem.
10 yards, put a .177 pellet into the mouth of a empty .223 hull? If you can hold it steady enough, the rifle can do it.
Right out of the box, with no modifications, it will out shoot most shooters
I see you have done business with Walkonking.
Yes I have, and no complaints.
I did try the ar-15 type pistol grip on it, because the “chicken wing” grip is ugly, but went back to the factory chicken wing as it is better suited For offhand shooting, and more comfortable when in the firing position.
That grip surprised me also. It just fits so well. The only thing that would be better would be a custom shaped one like on the precision 10 meter rifles.
Have you put an insert into the end of the frame?
Yes I installed a AirForce end cap and got with a friend and 3D printed a baffle set.
You would think that a 10m pistol style grip would be a good idea, BUT..
The grip on a 10m pistol is designed to fit your hand in one position, off handed standing with 1 hand.
The grip on these rifles are designed to be shot from multiple positions, so the grip needs to be flexible in its shape to accommodate the different stances in 3 position shooting and other disciplines too.
And if I remember correctly there are rules about the grips on the rifles in 10m Issf guns, (used to be UIT, but that shows my age. )
But I may be wrong, it’s been many years.
But for your own fun gun, it would be cool to have a custom grip to fit your hand.
The angle would be all wrong for a pistol grip. I was thinking of a rifle grip. They are close to the same shape as the Edge, but are not ambidextrous.
I was more thinking of a condor .25. my new Gauntlet 25 is awesome. But…
I had a condor in 22 but it’s power level was so close in power to my Talon SS but in a larger package that after shooting it I decided it was more than I needed.
I have owned and sold many air guns but I have only sold one Air Force airgun and it was the condor.
I love the fact I can shoot HPA and have almost 40fpe, and then screw a co2 tank on it and get 12fpe, and have several hundred shots per 7 oz co2 bottle.
It’s a perfect afternoon plinker.
When Air Force airguns were first introduced I thought they looked extremely cool, but kept telling myself that with the high scope mount they had to be in accurate, and I kept believing that for many years, until I finally had the chance to shoot one.
Now I’ll never be without one.
I bought a used Condor that had an offset adapter and regulator. I can’t find my shot string but I got over 100 shots of 16 grain JSB pellets at around 850 fps if I remember right. The offset adapter dropped the tank to a more comfortable position but between the adapter and reg it became a long reach. I found out that the gun had several stripped out barrel support screws. I landed up selling it cheap to a friend. Looking back I wish I had bought a replacement frame and kept the gun.
Outshooting most shooters is a hallmark of all 10-meter rifles. And you’re right; the Edge will do it.
That looks like it should be illegal in competition.
At some point, please tell us the story of the US made sights.
Optical sights are not permitted in competition with few exceptions.
The AirForce peep sight is a great story that’s mostly been untold. You will find out more about it in Part 1 of the 7-part report on the Edge.
Looking forwards to discovering more on this rifle. I like innovations, so please highlight them all. The bold arraignment is interesting with all of the slots and graphic instruction.
Good Day to you and to all,…….. Chris
Read through his blog on the Edge. It is indeed a fascinating air rifle. Also, like all other AirForce air rifles you can do so many things with it. These air rifles are a tinker’s dream come true.
Many years go I asked AirForce if I could purchase the rail mounted Edge forearm rest for my Condor Bounty Hunter and they said no. So much for customer service. ?
That rail wouldn’t attach to your rifle. It sounds like they prevented you from making a mistake.
It should attach to his rifle without any problem. It bolts to the lower 11mm rail unlike the standard forestock which bolts directly to the rifle.
I thought Bob meant the adjustable Edge rail! That one slides on a rail the Edge has but the Condor doesn’t.
I find it strange that they would not do that. I have worked with Rachael many times over the years and have enjoyed excellent customer service. The only possible reason I can think of for them to deny your request is that for many years they could not meet production demand for the Edge. They may not have had the extra parts to do such.
This particular Edge is much quieter than the off the shelf version. there is a baffle insert in the front of the frame. It makes this air rifle so quiet, all you hear is the cycling of the action. I was intending to quieten that down some, but I had not found my round tuit yet.
Just so we are perfectly clear with one another, if for some reason you want to get rid of this air rifle, I want it back. 😉
The same holds true for your Webley straight grip Senior. 😉 🙂
LOL! Right now that is hanging on the wall with the Webley MK II Service. I seriously doubt that set will be broken up. Not by me anyway. 😉
To give credit where due, Lloyd Sikes designed and built the firing chamber for me. During our first road trip for the GTA Fun Shoot we spent many hours discussing this air rifle and what I wanted to do with it. He then pulled out one of his magic spreadsheets and plugged in the desired velocity, caliber, barrel length, projectile mass and regulator operating pressure. That determined the volume of pressurized air we needed.
I’ve seen Lloyd do that, and it always works.
I so enjoy any time I get to spend with Lloyd. It is such a joy to sit down and discuss ideas with him, talking back and forth, and then work out the engineering for such.
Something else about this trigger that BB did not mention. The first stage take up is less than 1/8″. When fired there is almost no over travel. Dead stop.
No, this is not a Feinwerkbau trigger, but it is every bit as nice if not better than the Rekord.
I didn’t measure stage one but I did say that it is incredibly short. As for the overtravel, I never noticed it until now. But you are right — it’s there. This trigger wouldn’t be allowed in the NRA Junior class competition — it’s too nice!
When I explain the history of the Edge development I will try to explain why the NRA and CMP are mandating things we airgunners wouldn’t like (trigger pull weights, top velocity, cost).
Another tidbit is modifications that can be done to the sights.
The front sight is a proprietary size, about 19mm I think. They used to supply you with three different iris sizes you could swap out, but now I think they only provide one. Mike Reames made an adaptor bushing for his to accept an 18mm adjustable iris. He can adjust his to whatever size he desires.
On the rear sight block the aperture is threaded on and can be removed. It is the standard threading, allowing you to install an adjustable aperture.
It is incredible how versatile this little air rifle is. Your only real limitations are your imagination and your wallet.
As you can see, the Edge can easily be converted from a 3P Sporter to an entry level Precision air rifle. Perhaps you should put a bug in John McCaslin’s ear about developing a kit for such. With all of these out there it could be a good way for many youngsters to make the initial step up to the next class without buying a $4000 air rifle.
Well, I’m definitely going to show him this rifle before I take it back to a 10-meter gun. This could become a new product fairy easily.
That would be awesome cool! I would like one. How about neon green and black?
I like the air booster chamber.
And yep Lloyd does some cool work. He worked up a double resivior for my .25 caliber gen1 Marauder I had. Very nice I should say.
Lloyd should get together with AirForce and get something figured out on the air chamber and sell it as a accessorie for the AirForce guns.
And the 25 shot count is reasonable. My .25 Condor SS gets 25 usable shots with the factory bottle. And that’s from 2450psi down to 1700psi.
This Condor SS is my 3rd AirForce gun and I have to say they are nice well built guns. And love the interchangable barrels and all the accessories for them AirForce makes. I will not be letting go of my Condor SS anytime soon that’s for sure.
And got something to show here real quick.
I set this phone book out at 50 yards leaning up against my Caldwell spinner. The phone book wasn’t solid so it bumped when the pellet hit. The phone book is about 2 inches thick.
I shot the Maximus at the top left with JSB 18 grn. dome pellets. And it didn’t pass through. It stopped 30 pages short from going through. It was the only one that didn’t go through. So I was able to recover that pellet. And it was interesting. I took a picture of the front and back of the pellet and with a pellet that was not shot beside it. Check out what it did. It mushroomed into a hollow point. It made a big tear on the pages. The .25 Condor SS made the biggest tear but was a pass through.
But all pellets went in as a small diameter. The .177 Gauntlet passed through and that was shot at the top right with JSB 10.34 domes. The Bullmaster is at the bottom right and with the Winchester 9.0 grn. domes and was a pass through. The Condor SS is the bottom left with JSB 33.95 domes and a pass through.
Here’s the front of the phone book. You have to zoom in. And I’ll post the back of the phone book in a minute.
Her s the back of the phone book.
Here’s be the front of the Maximus pellet.
Look how it mushroomed into a hollow point.
Here’s the back of the Maximus pellet.
Here’s the front of the Maximus pellet.
Look how it mushroomed into a hollow point. I thought that was pretty cool.
I like mushrooms.
We are now back to the ongoing argument between the 9mm and the .45 ACP. Due to the higher velocity of the 9mm, it has a higher muzzle energy than the .45 ACP. However, once the 9mm has passed through the intended target, what remaining energy it has is wasted.
Right. What was interesting was the Gauntlet and the Bullmaster bumped the phone book a little when it hit. The pellet went through so fast it didn’t have time to transfer the energy.
The .25 Condor SS didn’t even seem to move the phone book. Matter of fact I thought I missed. It went through so fast to. Even though it is a bigger diameter pellet then the others. It’s just making so much more power than the other 3 guns.
But when the .22 Maximus pellet hit the phone book it jumped. Definitely good energy transfer.
But all it would take is some velocity change on all 4 guns and all the results could change.
As I say. Just because you have a small caliber like .177 doesn’t mean it can’t take care of business. If it’s accurate and the velocity is there it can be just as effective as the other calibers at it’s given distance.
Never underestimate a situation. You could be in for a surprise.
The only real issue with the .177 is loss of velocity and accuracy at longer ranges and the lack of mass. The newer heavy .177 pellets are promising.
Yep when your locked in at a velocity and you find your guns favorite pellet it then becomes a distance thing.
And that’s not just .177 caliber it’s all calibers. And not just air guns.
But yep what is interesting is I have shot starlings with the Maximus, Gauntlet and Condor SS out at 50 yards. When I hit the starlings with the .177 caliber Gauntlet they actually flew about 20 feet. It’s like they didn’t even know they were hit it went through so fast. Now the Maximus you could actually see it knock the starling when it hit. The Condor SS also knocked the starling but made a loud pop when hit and feathers everywhere. No need to explain what the other side of the starling looked like.
But yep getting to know your gun will definitely make a difference if you pest or hunt with it.
Kind of like the difference between a 5.56 NATO and a .50 BMG.
I am fortunate / unfortunate that I do not have an issue with starlings being about. Apparently they do not like wooded areas. I never see starlings around my house. I know I would really enjoy a target rich environment but I am also glad I do not have to deal with those buggas.
Yep with the 5.56 and BMG.
And yep you are probably lucky you don’t have the starlings. They can make a mess of things if you know what I mean. And they are in town. But you see them lined up for a half mile on the telephone wires by the corn fields in the country or if they aren’t on the wires their in the fields. It seems like they just keep multiplying. There’s more now it seems then when I was a kid.
I’m old and slow; before I read this report, I went back and read the 7-part report on the basic Edge.
And that led me to read the 3-part report on the sights.
All I can say is, “Wow!”
This gun is a real solid piece of engineering,
as well as something a tinkerer could spend years messing around with all the possible configurations
…which would be time well spent, of course. =>
Even though I’m not a competition-oriented shooter, I found all these reports interesting
as ALL aspects of airgun shooting are of interest to me…and many others, I’m sure.
take care & God bless,
Well I received two very good reasons why AirForce would not sell me the Edge forehand grip. I figure it was about the time they started producing the Edge and the two are not interchangeable, a misunderstanding perhaps. I believe I would have had to modify the original receiver mounting screw also.
Apologies to AirForce. I just don’t recall the reason given at the time if there was one.
I have lots of alternate ways to make one using upside down M4 risers or other types with adapters. I just snap on some UTG rubber Weaver rail pads and I’m good to go. Had plans to install a long ventilated paintball barrel shroud with some rails installed but I lost my Round Toit…for now !
That works also.
For a time I had a picitinny rail on my Edge forestock. I put a hand stop to the front and covered the rest with rail pads. That was sweet. I could wedge my left elbow into my chest and push forward on the hand stop while pulling the air rifle tight into my shoulder.
Hey all, in this modern-cell-phone-pasted-to-the-ear, tweeting, Instagram, “what’s the latest?” world we live in,
no one has time to go back and read yesterday’s news, haha. =)~
Hence, here’s a pic from a comment I posted yesterday for B.B.
It may be of interest to anyone who is contemplating one of those Umarex Colts on which B.B. has reported.
(They are way cool! And the 7.5″ barrel increases the practical accuracy. =>)
They made a good move doing away with the bright shinny brown plastic looking grips that were on the first Marshals edition, Totally wrong for a weathered pistol. Not sure if it was my advice they took or a collective response but they seem to have worked things out just fine now.
Bob, I’m glad they took your advice; this thing is pretty cool. =>
You don’t have to convince me. I own over twenty of them. I see P/A is offering a lot of external parts like gold cylinders and hammers, barrels and such to customize them. Not too cheap though. I would like to see some real quality custom design grips for the shinny ones and real wood for others. Eventually I will need to plant more money trees.
“I own over twenty of them.”
Cool; so I’m ‘preachin’ to the choir’ in your case. =>
Yes, I would love to see some real wood grips available for these fine revolvers!
Yes I did, an AirForce end cap, and I got with a friend and 3D printed a baffle setup.
I am confused as to why the firing chamber added power and also why it reduces shot count. If this had been added, like I did in my .22 Maximus, I can see a reduced shot count because the reg. is now taking up air storage space. The set up on the Edge seems to be placed (between) the (regd. tank) and the action, and appears to be nothing more than a post reg. air storage device,… which is good. The Maximus has a storage sleeve, post reg., but the gauge still works. As I recall, it was a matter of leaving an O-ring out on the sleeve.
It’s simple. More air is being used for every shot.
The regulator is a door. One person can walk through the door at a time. The Edge firing valve has a small space — a vestibule for 5 people to stand in, once they have walked through the regulator door. After every shot the regulator door opens again and five more people walk through from the waiting room (reservoir) into the vestibule, waiting for the outside door (the firing valve) to open.
The firing chamber/vestibule in this Edge is a space that’s large enough for 25 people. That’s five times as many as before. When the outer door/firing valve opens now, all 25 people can walk through. Twenty-five people can apply much more push than five. But if 25 people at a time walk through the outside door, the waiting room will empty faster.
Pretty good! 😉 I am a fan of analogies myself. My understanding of the air chamber is an (insurance) that more than enough air can be supplied. Once the pellet leaves the barrel, the valve shuts and no more air is required. As I recall, the regulator in the Maximus did not reduce fps by much (after several adjustments), but did regulate the shots to a much tighter spread.
Looking back at notes:
Reg. = 27 shots, 1 =779, 27 = 776, spread 3 fps
Non-reg = 27 shots, 1 = 806, 27 = 724, spread 82 fps
That is (with) reducing tube volume. I do fill to 3000, but did that with both set-ups.
So,… still a bit confused, but will leave it lie for now. Work night. I trust you as you have WAY more experience than I.
I’ll give clearing up your understanding completely a go…
A Firing Chamber (also called a Plenum) uses the regulator to meter a preset pressure from the supply cylinder into a predetermined volume and wait for you to pull the trigger. Instead of depending on a BALANCED valve to load air from the supply cylinder into the barrel (that is just enough volume of air at the right pressure) to accelerate the pellet to the muzzle and NOT a bit (REALLY difficult) more. You can compute the volume of the barrel (and the Firing Chamber/Plenum), you can compute the pressure needed until pellet barrel exit to drive and attain the FPS desired.
F=MA (Force equals Mass times Accelleration) minus some constant vallue for overcoming bore/pellet friction (derived from a big equation not needed for this discussion.) There are other issues in the M of the equation: to include the work that the available pressure needs to do to accelerate the pressurized Mass of air down the barrel behind the pellet as well as moving the Mass of the air in front of the pellet in the barrel at the start of the pellet moving down the barrel, and finally, minus the loss of pressure to adiabatic cooling of the pressurized air in the barrel and Firing Chamber/plenum behind the pellet. The typical regulator is so slow that the pellet is long gone and the valve closed before it opens to start refilling the Firing Chamber/Plenum. The specifics of all that requires the use of Differential Equations to be exact! We don’t need that ; ) We can approximate it by listening to the report of the shot. You can add or subtract from the volume of the Firing Chamber/Plenum until the report lowers in db or your chronograph (better way) is giving you your desired velocity. You could also use the Firing Chamber/Plenum to give you an exact shot count from a given volume supply cylinder at a predetermined starting pressure; as well as to raise or lower shot count simply by changing the Firing Chamber/Plenum volume; you get a resulting FPS that you live with to get the specific shot count…Nothing is Free!
Thank you for that explanation. I did catch “most” of all that. 😉 My first glance at your comment was at 3 AM and no coffee yet consumed. Thus,.. the delay in reply. Plus,… I was out early today. Not all regulators are slow to recover, as I am sure you know..
As I said to B.B.,…. “You know/understand/comprehend more than I, therefore I trust your take on the matter”.
“We don’t need that 😉 ” ,……….. I like that! I do indeed try to keep things simplistic. Then on the other hand,….. if something sparks my interest real hard,… then all bets are off. At which point I often find myself over my head,………….. 🙂
The air in the chamber has already passed through the regulator and is released immediately then followed up by air from the regulator. It continues to travel down the barrel while trying to refill and pressurize the chamber again until the valve closes. Like a double whammy air charge. So like BB said there is more air available for the shot.
More air is released than would normally pass through the regulator for each shot.
Like having a bigger valve with a weaker spring. Think of it as a turbo charger on a car.
Good point. Air is being supplied/made up at the (same time) that air is being consumed. Still,…. I am not sure I get it. See post above to B.B.. Maybe the Edge is under powered to begin with? From what I gather, it is made that way to hold down the fps for competition rules. Maybe apples to oranges? One is choked down and this improves it,.. and on the other,…. nothing is choked down,,,, but a regulator controls the fps spread better. All in all, interesting.
I think you figured it out but don’t quite get the reason for it or what he was up to. He simply wanted an accurate rifle with much more consistent power.
The rules for competition were thrown out the window. It is no longer eligible for use in competition after the addition of the chamber.
By adding the chamber he took an extremely accurate LOW powered regulated rifle and turned it into an extremely accurate HIGH powered regulated rifle without doing anything else to the rifle. The regulator was untouched and nothing else was either.
It is easily reversed to it’s previous power by simply removing the chamber.
I would like to say it’s like adding a customized computer chip to your cars engine control module to gain an extra 100 horse power without changing anything else. Remove it and your car is back to normal again. (Assuming you put the original chip back in. )
Or how about this…. All the pressurized air in the chamber effectively turns the rifle into an unregulated rifle for more power. It no longer passes through a restrictive regulator to shoot the pellet. When the regulator refills the chamber it is always to the same amount so the unregulated air in the chamber has the same power each shot.