How Do BFAs Work?
 

I'm wondering how a blank adaptor allows a slide to cycle with such low power loads.

They block the gases from escaping the muzzle so this gives the gases enough power to kick the action back.

Of course, it also tends to make the actions much dirtier and wear them down faster than live rounds.

The the weapon is not a direct blow back then it needs modification for it to work with blanks.

Something like an AR needs no more than a BFA but something like an M1911 needs adjustments to the barrel including a muzzle plugs and milling down the part of the barrel seen in the ejection port.

At least that's what I think I know.

Maybe I'm wrong about this (Steve can correct me), but don't 1911s need the ejection port widened because of the fact that blanks have extended brass heads to hold the extra powder? I imagine that this would present problems in an un-modified 1911 because it would have trouble fitting properly through the ejection port while the gun was cycling. Or, at least, there would be a higher risk of a stovepipe malf.

You are correct on the ejection port on the 1911. The same goes for all semi-auto pistol except Beretta 92, Taurus PT99, Walther P-38. We remove material forward on the ejection port for the spent bras to rotate clear. Also the ejector has to be trimmed to assist on the ejection on some pistol but not the 1911. The longer brass is used to form a projectile shape crimp and we used the same case and crimp for at least four different loads. They will eject fine unfired from a unmodified ejection port but once fired will have a hard time clearing without mods.

So thats why all the old movies have nothing but p-38s and now adays its the taurus/beretta 92s dominating the screen.

Well, yes, I've been told by several armorers that the Beretta/Taurus 92 is one of the most reliable blank guns, and one of the easiest to convert.

OK, thanks for the info. Does the crimp hold any extra powder if you're doing a full-flash load in the cartridge?