If....
..now what would be interesting is if it had a real chainsaw bar and chain, in place of like a bayonet. It has to work, too....even just like an eight inch bar, something....
I was thinking of a shotgun I wanted to build once when I worked in a gunshop..never built it but..here's the idea. It's a bullpup semi, with a forearm strap/brace. Something like a wrist rocket brace, but say a strap, velcro would work, so it locks in good. The action sits over your arm, with the balance point right there in your grip, so you can truly use it one handed. Plus, being semi, it would help with the recoil to keep it controllable. That beretta action would be nice to start with...
That's the weak link on pump combat shotguns, no way to use one one handed..not easily anyway, you know what I mean. If one hand or arm gets injured, that's it, you got an awkward club to use.