Okay, so not apples to oranges since that's a semi auto, but years ago I watched a friend of mine shoot a knock down steel match with a pump gun with a collapsible AR stock. When the match was over, he looked like he'd been in a fist fight. His face was swollen and bruised from that thing beating the shit out of him. (sold it soon after)
So if you're building a gun to be small, stashed away and hopefully never really shoot, maybe. If it's something you're actually going to used, I'd look elsewhere.