If you look it up on Wikipedia they claim that its recoil is similar to a .45 Wikipedia is a questionable source at best. They talk in some detail about the caliber, and from what I read I don't see how it will ever gain commercial acceptance. It's statistics are no better than anything else we already have, with the possible exception of a bigger hole (which may in fact be a big deal). My thought was that it would survive for guys who love wildcat cartridges because they get bored with the same old same old. Not that there is anything wrong with that either. Wiki claimed that there was talk about the FBI field testing the 50 GI, but that was when it was only available in a 1911. I suppose if the FBI were to adopt it, the caliber might gain some commercial following. I could be wrong, but it seems like there is a trend towards 9mm and .22 due to the cheap ammo available. So unless you buy dies to reload 50 GI, whats the point in buying the gun.
Old thread, but interesting...I'd never heard of the .50 GI.
Excessive recoil apparently wouldn't be an issue with that cartridge, because it doesn't have any more energy than the .45 ACP. So the plastic frame would handle it just fine.