[SML] Stage guns

[Duncan Mahoney]

Jerry Durand asks:

"I was wondering how semi-automatic pistols like 1911 ones are made to cycle with the tiny loads used for stage/movies.  Just saw someone in a movie shooting away without the slightest hint of a recoil, so the charge must be tiny.  Maybe a muzzle restricter to increase the pressure?"

The loads involved are not necessarily  tiny, but there's no recoil because there's no bullet getting accelerated and the escaping gas has little mass.  The moving parts of the gun create forces that are mostly equal and opposite. You surmised correctly, the barrel is plugged and ported with a tiny hole precisely sized to the power of the blank load.  This builds enough pressure in the chamber to cycle the gun.

For theaters without the resources to afford rentals from ISS, there are many commercially available semi-automatic blank guns that utilize a 8mm rimless blank, and a few using a 9mm blank.  All of these will only cycle with a full load.  If you want a gun that will cycle and fire "half-loads" or "quarter-loads", you will need to get it (and the blanks, all custom made) from an entertainment armorer.  But...if you start with a "real" gun of large caliber, a "half load" may be louder than the 8mm full load blanks.  Some years ago we rented the "half-load" M1911 from Gibbons (sadly, now out of business).  In a black box theater the .45 caliber "half-load" was deafeningly loud, and the 15' long plume of flame that erupted from the port was enough to convince the Director that the "shot" should be done with a sound cue


Duncan Mahoney
Director of Technical Direction
Associate Professor of Theatre Practice
University of Southern California School of Dramatic Arts