@triplermunitions posted a video of a shorty 1919 being fired full auto. Given the barrel reduction and therefore weight reduction, this could be a great candidate for the steadicam rig. What barrel length do you think that shorty 1919 has? Looks like 12-14 inches? The muzzle flash is quite significant.

Here is another video of them shooting a 1919 offhand.

A brief google search came up with this website on short barreled 1919s and the challenge in making them.