New Pellets in Holland

[SeanMP]

Good question. I've been pondering that one myself.

It absolutely will work but I'm not sure about the accuracy. There are all kinds of conversions for AR type platforms to fire the 22lr down a .224 barrel.

Traditionally the 22lr barrel is .221 to .2215 for match and a little more sloppy in semi auto's like the 10/22.

The critical factor will be the sealing band on the bullet ( those are absolutely 22lr sub bullets...) If it's .223+ then accuracy should be do-able. It may be a try and see. Possibly a lapped .221 barrel may be the winner except all the .221 barrels produced have a 16 rate and I agree we need at least 15.

I have wondered for a long time why wouldn't a small bore setup work equally as well using air as the power source. In my mind it should work. Both are optimally sub sonic and match ammo is specifically made to not have enough pressure spike to hammer the bullet.

[SeanMP]

I just found this spec on the Redman liners. 0.223 but once again the rate is 16

SPECS:
4140 steel. .223" (5.6mm) groove diameter for .22 Short and Long Rifle (LR), 1-16 twist (LR) or 1-20 twist for Short. 5/16" (7.9mm) O.D.,25" Liner - 26-3/8" (67cm) overall, 25" (63.5cm) usable length. 32" Liner - 32" (81.2cm) overall, 30-5/8" (77.7cm) usable length. Not chambered.
Catalog page 162

[SeanMP]

Ya I'm looking forward to it Al
Just a few minor details to sort out yet and we'll be off to the races.

I'm pondering the idea of using two solid blocks for the breech and valve arrangement rather than the traditional tube stack...not sure how that will pan out but .....

[rsterne]

I've been giving this project some more thought, and I can see why most (if not all) of the competitors have their rifles tethered to a SCUBA or SCBA tank.... First of all, to get 950 fps with the 41.5gr. pellet (83 FPE) and have the valve close when the pellet is half way down a 26" barrel requires about 2800 psi at an efficiency of 0.90 FPE/CI.... That would use 92 CI of air (at 1 bar) per shot.... If you had a 22 CI, 3000 psi tank (2.6 CF), the pressure would drop 61 psi per shot.... If you started at 3000 psi, and shot 7 shots, you would be down to about 2600.... Using less pressure would drop the efficiency, and eventually you wouldn't have enough to get the velocity/energy required even with a dump shot (which is very wasteful).... Sooooooo, it's either not many shots, or a very big reservoir....

If you tethered the same gun to an 88 CF SCUBA tank, you might get about 200 shots from 3000 psi down to 2600.... If you regulated the output to 2800 psi, maybe 100 shots.... The best way to go, would be to tether to a 4500 psi SCBA tank regulated to a 3000 psi output and tune the gun accordingly.... The higher the pressure you use, the more efficient, because you can close the valve sooner.... That also makes the gun quieter, although these things will be LOUD anyway.... In the example above, the residual muzzle pressure would be about 1340 psi (ie nearly half the tank pressure).... Note that these numbers are all rough approximations, and there is no guarantee we can reach the required efficiency levels to produce them.... That said - GAME ON !!!

Bob

[SeanMP]

Your right the geometry would require some thinking. You would need to get the tank block far enough back to allow for a grip

[SeanMP]

Done deal
Two pieces of twill laid carbon fiber tube on their way

This will quell the chaotic vibrations and still allow the harmonic to be tuned

[rsterne]

Maybe we're better off to do a complete DIY approach.... Use the TJ's liners and cast and size our own bullets.... Lyman have a mold....

http://www.lymanproducts.com/lyman/b....php?entryID=1

I don't see a diameter, though.... I assume they would be big enough to size to 0.224" with a Lee sizer....

http://leeprecision.com/new-lube-size-kit-.224.html

Maybe you should get the barrel liners and chamber them and I could get the mold and sizing die and make some bullets?.... I already have the pot, ladle, and press.... just a thought....

Bob

[rsterne]

The other email contact didn't work out and suggested Drummen as the place to purchase the bullets.... I see you have asked about the diameter, any answer yet?....

Bob

[SeanMP]

Game on indeed. I was out picking up material today so I grabbed some 12L14 to start poking away at the upper and lower block. I had to settle for 1 1/2" hex bar
How many shots does your Quackenbush get on a tube fill?

Looks like I better look at using 1" ID tube. That would give about 5 shots off the tether. Certainly viable as a hunter

With such a heavy long projectile that is bound to increase the dwell time allowing the pressure wave to build. Do you think this could have a positive effect on the efficiency?

[rsterne]

My concept for a dual tanker is more like this....



I would either use two identical 22 CI (360cc) tanks, or possibly a 490cc (30CI) Airforce Tank for the rear one.... The 22 CI are 11.4" long x 2" OD and the 30 CI are 11.8" long x 2.5" OD (roughly).... The lower block would house the valve, hammer, and spring.... the upper one is the breech.... I could use a PRod trigger assembly, although there may be a better choice.... Too bad Blue Fork Design isn't doing his grip frames any more....

With the 22CI tank butted up against the back of a PRod trigger group, and with no buttplate, the length of pull is 15".... That's a touch long, but I could live with it.... I think the height of the top of the tank would be close to the right height for my cheek to line up with the scope (depending on breech height).... The 2" tank, being slimmer, might be better in that regard.... Relative to the breech, the rear tank is quite a bit lower than the Condor, eliminating the high scope rail.... so that's a good feature....

Just all blue-sky thinking at this stage.... The RVA would still be the problem, plus a seat for the hammer spring.... and the hammer might have to have the sear catch in the middle or near the rear to latch onto the sear.... The valve would draw from the front tank, the passage through the block between the tanks could be just 1/8" and still work just fine....

Bob