Wow. That's even less practical than a "normal" obrez.
WARNING: FIREARMS PEDANT MODE ENGAGED BEYOND THIS POINT
At that length the chamber is missing, let alone the barrel, so with the bolt closed, most of the cartridge would be sticking out of the muzzle. The only thing holding it in place would be the extractor. I'm not sure it would even stay in place to be hit by the firing pin if you tried to fire the gun, but even if it did, the unsupported cartridge case would just detonate like a tiny grenade.
I suspect M200 knows that, hence the sweatdrop. :)