# Distance a 12g CO2 cartridge can launch a...?

The design of the barrel would (VERY) roughly look like the image at the bottom. The cartridge would be in a housing unit at the butt of the launcher. It would be set it off in a to-be-determined way, shooting out the cylinder(2 2/5inch diameter, 8 inches long, ~12 oz) that would be resting in front of it.

air, slightly different mass has 40-100kJ/kg (say 75 for the sake of it) of stored energy. 12 grams thus would be 75kJ * 12/1000 = 0.9kJ (900J) of energy.

If you could extract that energy from the gas 'instantly' and 100% efficiently convert it to kinetic energy, you'd assume Ep = Ek. Ep = 900 Joules. Ek = 1/2 M*V^2. Cartridge is 56 grams full, thus 44 grams empty.

900J = 1/2 0.044*V^2

1800/0.044 = V^2

40909 = V^2

V = root(40909)

V = 202 m/s = 662 fps = 727km/hr = 451 mph.

Thats of course assuming absolute ideals, and real world would be a LOT less than that.

How far you could shoot something going that speed at that weight would again be a nontrivial calculation...

if you extracted that energy in even 10% efficiency, thats a brutally dangerous projectile capable of travelling a LONG way.

http://en.wikipedia.org/wiki/Compressed-air_energy_storage

What diameter on the ~12 oz cylinder, what barrel length?

L