Your 30 grains of 'whatever' was ejected at 1200 FPS, the total kenetic energy of which is calculated by 1/2 MV2. There is an equal and opposite force. How the velocity was obtained is not relevant.

Even an airgun has propellant ejecta, since a large mass of air exits the muzzle. Nothing changed state in that case, but the expanding air has mass just like powder gasses.


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