Your powder is changed by chemical action from a solid to a gas. The gas leaves the barrel at high speed, thus it's "ejecta" as much as the shot and wad. Guess what? The laws of chemistry tell us that the mass of that ejecta is exactly the same mass as the original mass of the powder.

If you doubt this effect, stop by the cape next time they launch a rocket. This is quite a convincing demonstration.

Fire a 300 Weatherby in a rifle with a removeable muzzle brake, with the brake on and with the brake off. In cartridges of that class the gas ejecta is 1/3 of the total ejecta and the brake redirects a significant portion of the gas sideways. The reduction in recoil is dramatic.




"The price of good shotgunnery is constant practice" - Fred Kimble