I have seen a guy using a different shotgun scabbard for his M16, but that was with out optics and the mag removed. That scabbard should would with a mag in since it has space allotted for the mag, but unless the foregrip is right up against the magwell it probably won't work. As for optics... What type of optic? No rifle scope or larger red dot sight will fit, but if you are using something smaller (if that exists) then maybe. Probably not even then. I would recommend using an Irene Adaptive sling (http://www.airsoftgi...roducts_id=7444
) this is one of the best weapon retainment systems I have ever used.