A very similar gun to the one you describe is already manufactured by XP-Airguns in Kansas. It is called the Quigley - Scorpion .72https://www.xp-airguns.com/photo-gallery.htmlTaming the bark of a .72 will be the trick.
Well you can hunt with far less than 800fpe, what is the purpose of said gun? Not that there is nothing wrong with power.That is the length of the elusive hammer if I'm not mistaken, do you want to create that or something similar..73 and 30" barrel tou could get pretty close to your goal with that pressure but the bullet is very short. And its bc going to be low so not a long range gun.My small projectiles are pretty short for 20mm caliber and they weigh around 1600grCant imagine how short 300gr ~18.5mm would be.Marko
A very similar gun to the one you describe is already manufactured by XP-Airguns in Kansas. It is called the Quigley - Scorpion .72Taming the bark of a .72 will be the trick.
So would 0.2 CI per FPE be a good starting point for a "can" ?.... If so, then for 300 gr. @ 1050 fps, maybe 3" in diameter and 2 ft. long.... Of course a .58 cal at the same FPE would need the same size.... Bob
I presume you have already done the math, as a .73 cal lead roundball would weigh 583 gr.... and yet only have a BC(G1) of less than 0.1.... BC doesn't affect trajectory much, but it sure affects the downrange velocity and energy retention.... For simplicity I would go with a .58 cal, and shoot roundballs, which weigh 292 gr. and have a BC of about 0.08.... Keep the velocity at around 950 fps, the wind drift is less than it is at 1050, although admittedly the MPBR would be less for a 4" target, 84 yds. instead of 92 yds.... You should be able to get that velocity on 3000 psi, and you will find that reaching 950 is a lot quieter than 1050, unless you have a really long barrel.... If you have your heart set on 1050, that should be possible using 3500 psi.... With a MV of 950, that .58 cal roundball will arrive at 100 yds. with over 400 FPE of energy.... The size of valve you will need for a .58 cal will be much smaller, which means less hammer strike, easier to cock, less air used per shot, easier to quieten it down, etc.etc.etc…. Just a suggestion....Bob
Bob has very good points there, taming down .73 is going to be downright impossible.Marko
Marko, you are quick to say it is impossible, but from what I am hearing... a 3.6" x 18" can would suppress a 300gr 72 cal at 1050fps and 735fpe to be backyard friendly. I would say that is far from impossible. If you think a can that large is goofy. That is merely another problem to solve. A possible solution is not making the can round. See the example below.
fpjeepy, Yo're right, it is quicker to say than do.You only need to tame this. Ok, it is bigger but you get the idea. It is not a steam engine, cold weather is condensing the most of air coming out from 20mm.There are only laws of physics against you unless you invent something to close the door right after elvis left the building...I'm not saying it is impossible but is it handy or practical? NO.
Is rkr's can practical? What if it was 75% larger in diameter? Do you disagree with 0.25 in^3/fpe?