Due to 922r, the M4 can't legally be imported with a collapsible stock or a normal-length mag tube, and you can't legally convert it to have those parts without replacing a certain number of foreign-made parts with American-made ones:cmdc said:I bought a Benelli M4 with the field stock, because that's what my LGS had in stock. I was thinking I would put a collapsible stock and 7 rd mag tube on it. When I looked online, the Benelli site listed their collapsible stocks as only for the models that came with the pistol grip. I haven't picked up the shotgun yet, so I'm wondering what the difference is. Does the field stock not have the same buffer tube? I'm confused. If I can't convert it, it's not the end of the world.