^^ We don't see the stock, but it's certainly not a Mesa Tactical adapter, we see the right side of the AR15 selector switch under the forward assist, they did cut an AR15 right in front of the forward assist, and they managed to bolt it to the shotgun, they also did cut the top of the upper receiver under the charging handle, we see the crappy filling job done there.
You know what? I think they did cut a bit of the shotgun too... is it a 870, a 500? What the hell man...
And that barrel "thing"? I don't want to know.