Quoted:
What do you mean "depending on which version you get?"
Can we get it clear in black-and-white (or in the case of this board, black-on-kind-of-neutral-gray) which Ultimak goes with which rifle?
.410 - Don't know.
20ga - M11-L, but this isn't a gastube replacement, it attaches to the gastube on fixed sight guns.
12ga - M11-L, but this isn't a gastube replacement, it attaches to the gastube on fixed sight guns.
.223 - M-1B (No Vent Holes) and M-2B (Vent Holes), but I believe you need barrel shims.
5.45x39 - M-1B (No Vent Holes) and M-2B (Vent Holes), but I believe you need barrel shims.
7.62x39 - M-1B (No Vent Holes) and M-2B (Vent Holes)
.308 - None that I know of.
I have the 5.45 and am contemplating getting a .308 and would love to know which rail to get.
If I am wrong, someone correct me.