They have prop guns that simulate real gun action. BTW I read that article as well... in that article they also said they need to record real gun 'noise'.... this is totally false. Real gun noise is nothing like you hear in the movies. A real gun is so high pitched as to sound 'phony' if you've only heard a movie sound track of a gun.
When I was in the Army they had a weapon... and so sorry I can't remember what it was called... that fired grenades by air. Not out of a barrel, it launched them. BUT my point is the damn things kicked like a mule. I have fired a .50 caliber machine gun from a free standing position, (no monopod, bipod, just hand held), and the kick, (recoil), from that was MUCH less that the air propelled grenade launcher.
You use "real" gun noise and the audience is going to rebel... it's a whinny ass "pop" compared to what they edit in for movies. It is LOUD, that's the only similarity. - JamesJM
