Airsoft Canada - View Single Post - Feed-paths on bolt rifles

Ghost Snake · June 9th, 2006, 03:10

Well you know, it was pretty hard to find. I mean, it was the first result when I typed in "ballistic calculator" on google. :wink:
http://www.handloads.com/calc/

When using the coefficient calculator, it doesnt accept bullet weights under 10 grains. So if you want the coefficient for a 5 grain bullet, do the calculation for a 10 grain, and then divide by 2. I did my calculations with a bullet diameter of .243 (roughly 6mm), weight of 10 grains, and I used HP as the bullet shape. This gave a coefficient of 0.021. My calculations were based on a 5 grain projectile, so 0.021 / 2 is 0.011. I used the HP shape because it was the closest to a pellet gun pellet.

A "blade bullet" though would be closer to the coefficient achieved by a boattail, maybe even a little better? Speaking of blade bullets, I wasnt able to find out for sure, but one source said that they were .34g. A blade bullet could potentially give you a coefficient somewhere around 0.025. But thats just a guess.

I spent over an hour trying to find a useable combination of bullet weight, velocity, etc. but I just couldnt get the energy low enough. I dont think a bullet weight under 0.34g (5 grains) would be stable. Leaving the coefficient and range out of it for a second. The max velocity a 0.34g bullet could be, before reaching the legal limit is 602fps. This wont give you very good range no matter what the coefficient. But keep in mind that even though it would be legal, there is no way you would want to play with that. If you are very careful about where you shoot a person, you could maybe get away with 2.5 joules, but even that is pushing it.

So, in conclusion, I personally dont think that rifled barrels and bullet shaped projectiles will ever be used in airsoft. And after using that calculator, I have also come to the conclusion that while the Asahi M700/M40 guns were cool, they were completely impractical for use in a game, simply because to be effective, the energy would have been way too high.

Another link that may help you is the fps/energy calculator on arnies. http://www.arniesairsoft.co.uk/?filn...s/fps_calc.htm

EDIT: Now that I actually look it up, 6mm is more like 0.236". Not that that would really affect the final results though.

June 9th, 2006, 03:10	#24
Ghost Snake Trader rating Join Date: Apr 2005 Location: Edmonton	Well you know, it was pretty hard to find. I mean, it was the first result when I typed in "ballistic calculator" on google. :wink: http://www.handloads.com/calc/ When using the coefficient calculator, it doesnt accept bullet weights under 10 grains. So if you want the coefficient for a 5 grain bullet, do the calculation for a 10 grain, and then divide by 2. I did my calculations with a bullet diameter of .243 (roughly 6mm), weight of 10 grains, and I used HP as the bullet shape. This gave a coefficient of 0.021. My calculations were based on a 5 grain projectile, so 0.021 / 2 is 0.011. I used the HP shape because it was the closest to a pellet gun pellet. A "blade bullet" though would be closer to the coefficient achieved by a boattail, maybe even a little better? Speaking of blade bullets, I wasnt able to find out for sure, but one source said that they were .34g. A blade bullet could potentially give you a coefficient somewhere around 0.025. But thats just a guess. I spent over an hour trying to find a useable combination of bullet weight, velocity, etc. but I just couldnt get the energy low enough. I dont think a bullet weight under 0.34g (5 grains) would be stable. Leaving the coefficient and range out of it for a second. The max velocity a 0.34g bullet could be, before reaching the legal limit is 602fps. This wont give you very good range no matter what the coefficient. But keep in mind that even though it would be legal, there is no way you would want to play with that. If you are very careful about where you shoot a person, you could maybe get away with 2.5 joules, but even that is pushing it. So, in conclusion, I personally dont think that rifled barrels and bullet shaped projectiles will ever be used in airsoft. And after using that calculator, I have also come to the conclusion that while the Asahi M700/M40 guns were cool, they were completely impractical for use in a game, simply because to be effective, the energy would have been way too high. Another link that may help you is the fps/energy calculator on arnies. http://www.arniesairsoft.co.uk/?filn...s/fps_calc.htm EDIT: Now that I actually look it up, 6mm is more like 0.236". Not that that would really affect the final results though. __________________