Maybe with the weaker stuff. IIRC, they ship complete pistols with Super 42 H3. Might need to play with a couple of different buffers.
Sent from my Pixel 3 using Tapatalk
I’ve got an 11.3” BA barrel, and it eats any brass ammo, no problem. Port is ~.070 ish. Maybe a little smaller. I’ve actually choked it down more for dedicated suppressed use. Sionics RGP and Colt 11.5” are in the same ~.070 neighborhood. I suspect it’ll be fine with any decent ammo. A good friend just bought one of these G 11.5” Super Duty uppers, so we’ll see soon enough.
I have a 11.5" Duty Upper (nitrided stainless steel, 0.068" port) that I use with their Super42 spring & H2 buffer. Has functioned 100% with various factory .223 & 5.56 loads.
https://i.imgur.com/TSfY14u.jpg