by B.B. Pelletier

Part 1
Part 2
Part 3
Part 4


AirForce Edge 10-meter sporter-class target rifle.

Today we’ll do something different and special with the Edge. This is the surprise I mentioned. I’ll install both an 18-inch barrel and a 24-inch barrel to see what effect they’ll have on the velocity.

Of course, this is possible only because all AirForce rifles use the same mounting system and all guns accept any barrel length in any of three calibers: .177, .20 and .22. Though the Edge is a little different than the sporting rifles they make, the barrels still interchange.

The 18-inch barrel can be installed and not show outside the frame of the rifle. It adds some weight to the gun, but it will still weigh under the 7.5-pound maximum of the sporter class. What I’m talking about is possible to do while staying within the rules.

I used the same pellets that were chronographed with the standard rifle that has a 12-inch barrel, so we’ll be able to compare all three barrels using the same powerplant. This should be fun.

18-inch barrel

…with Meisterkugelns
I installed the 18-inch barrel and tested it with all four pellets that were chronographed with the 12-inch barrel. One of those was the 7-grain RWS Meisterkugeln lites. In the 18-inch barrel, the light Meisterkugelns fit very loose at the breech, and three pellets failed to fire out the barrel altogether. Instead, they were crushed sideways in the breech by high-pressure air getting around the pellet skirt before it could seal off the breech. So, I shot only a few of these pellets. The few shots that exited the muzzle averaged 616 f.p.s., with a spread from 612 to 621. I’ll come back to that at the end of the report.

…with H&N Finale Match Pistol
The H&N Finale Match Pistol pellet averaged 605 f.p.s. in the 18-inch barrel. The spread was from 596 to 608. I’ll compare them at the end.

…with RWS R10 Rifle pellets
RWS R10 Heavy Match pellets averaged 536 f.p.s. in the 18-inch barrel. They also fit the tightest of all the pellets I chronographed. The range was from 533 to 544. I’ll compare them at the end.

…with H&N Finale Match Rifle pellets
H&N Finale Match Rifle pellets averaged 584 f.p.s. in the 18-inch barrel. The spread went from 574 to 593, for the largest total spread seen in this test (with the 18-inch barrel). I’ll compare them at the end.

24-inch barrel

…with Meisterkugelns
Surprisingly, the light Meisterkugelns fit the 24-inch barrel much better than the 18-inch. The average velocity was 636 f.p.s., and the spread went from 632 to 641. Comparison at the end of the report.

…with H&N Finale Match Pistol
Finale Match Pistol pellets averaged 604 f.p.s., with a spread from 595 to 608 in the 24-inch barrel. Comparison at the end.

…with RWS R10 Rifle pellets
The heavy RWS R10s averaged 545 f.p.s. in the 24-inch barrel. The spread went from 539 to 551. Comparison at the end.

…with H&N Finale Match Rifle pellets
Heavy H&N Finale Match pellets averaged 597 f.p.s. in the 24-inch barrel, with a spread from 589 to 606. That’s the largest velocity spread for the 24-inch barrel. Comparison at the end.

How do velocities compare between the three barrels?
Meisterkugeln 7-grain pellets
12-inch average — 563, spread 8 f.p.s.
18-inch average — 616, spread 9 f.p.s.
24-inch average — 636 f.p.s., spread 9 f.p.s.

H&N Finale Match Pistol
12-inch average — 524, spread 12 f.p.s. (taken from a 100-shot string)
18-inch average — 605, spread 12 f.p.s.
24-inch average — 604 f.p.s., spread 13 f.p.s.

RWS R10 Rifle (Heavy)
12-inch average — 487, spread 14 f.p.s. (taken from a 100-shot string)
18-inch average — 536, spread 11 f.p.s.
24-inch average — 545 f.p.s., spread 12 f.p.s.

H&N Finale Match Rifle (Heavy)
12-inch average — Did not test
18-inch average — 584, spread 19 f.p.s.
24-inch average — 597 f.p.s., spread 17 f.p.s.

Here’s what I take from this comparison. The Edge seems to benefit greatly from the 18-inch barrel. It gains significant velocity, and the velocity spread from the slowest to fastest pellet remains pretty much the same as with the 12-inch barrel. But moving to the 24-inch barrel doesn’t seem to add much more speed, and in one case it made the pellet go slower. The max spreads remain the same.

I don’t see an advantage to adding the 24-inch barrel, but adding the 18-inch barrel really perks up the performance. Also, the 24-inch barrel adds an additional half-pound of weight that may be unwelcome in the sporter class.

Here’s what I see. If you install the 18-inch barrel, you get higher velocity. The heavier rifle match pellets may become more usable at higher velocity. Or AirForce could trim back the air a bit and add a few more shots to the total. In other words, get back to the same velocity the 12-inch barrel gave, which would take a little less air in the 18-inch barrel. But I think 100+ shots are enough for the gun. I like the idea of faster velocity, which means no changes are required beyond switching barrels.

Another observation I’d like to make is that the Lother Walther barrels seem to have a break-in period. After 500-1,000 shots, they seem to shoot tighter groups. That’s just an observation of mine; I have nothing to back it up, but it does give me an idea.

If you recall, my groups with the Edge were criticized soundly, and other shooters around the country began posting much better results on the internet than the ones I shot. That reminded me–what do we do when a barrel doesn’t perform to expectations in the accuracy department?

We clean the barrel with JB Non-Embedding Bore Cleaning Compound. Benchrest firearm shooters swear by JB Paste, and I’ve learned over the years that it often brings out the best in a barrel, so I’m going to clean the 12-inch barrel and re-shoot the accuracy test.

And, yes, to answer your unasked question, I will also shoot for accuracy with both the 18-inch barrel and the 24-inch barrel.

That’s it for now. I hope this revelation was worth the wait. I think it’s a pretty dramatic illustration of how barrel length affects pneumatic operations, and we are fortunate that all AirForce guns allow for it. We don’t have to just experiment; we can actually change the performance of the production rifle in a dramatic way.