I bought an MOE stock from a buddy thinking it would go on one of my mil-spec AR rifles, but it wouldn't fit on any of the tubes. However, it fit nicely on the MP 15-22, so that's where it lives now. So, the one that fits non-standard tubes is the one you're looking for I think.
I would say mine was getting muzzle swept twice by a couple of obvious novices at the rifle range, with a hot rifle, safety off. I told them both if it happened again I was going to shove the rifle up their asses. They packed up and left.
I know! I'm currently high bidder on a Sig TacPac 1911 on GunBroker, nothing I even thought about owning, but I saw it and bid. Voila, another gun may appear in my safe.
Regarding the 15-22, also a quality rifle and a great shooter. I have one, shoot it quite a lot. Only issue I've ever had is with Remington golden bullets, which isn't with the rifle but the ammo. Only my GSG-5 feeds that stuff reliably.