Slow motion video of the firing of a flintlock shotgun
Note the speed of the development of the 'flash in the pan' and the delay in recoil. There is no torque reaction here because this is a smooth bore shotgun, so no rifled twist to the bore to rotate the gun on firing. See how the blast of firing has forced this very experienced shooter to close his eyes due to the flash coming so close to his head, thus making the case for the wearing of eye protection (he is in fact wearing ear plugs, so no problem with hearing damage).
April 2010