Originally Posted By RealFastV6:
I've been told a regular M203 bolts right up. No modifications \ rail mounted grenade launcher necessary. Just remove the lower rail and off you go.
It'd be pretty silly to have the cutout in the barrel otherwise, no?
I didn't know for sure it wouldn't. Correct me if I'm wrong; the M203 has a little nub at the bottom that goes into one of the teeth on a barrel nut. If the 6940 doesn't have a place to put the nub, then it won't work. Also, the M203 has a ring that goes inside the barrel nut. If the 6940's barrel nut won't let that go inside, then it won't work. Does anyone have any pics of the barrel nut?
Also, the M4HB doesn't allow the mounting of an M203, yet has a step down.