Firing pin strikes primer, primer ignites powder, powder burns and turns into gas, gas propels the shot cup down the barrel, shot cup exits barrel and falls away from shot column at @ 7m, shot column begins to string out and form circular pattern.
The priming compound is spun into the rim of the case, and, when the firearm's firing pin strikes and indents the rim of the cartridge, the priming mixture ignites and in turn ignites the...