Would this RIS work on the ACM M4?
Also, when I pull back the bolt on my gun, the hop up wheel moves towards the delta ring like 1/3 of a centimeter. Would this cause anything bad to happen? My magazine is shot, so I really can't test it out.
Colazel:
You can buy GHK magazines from RA-Tech.
Also, are GHK magazines compatible with the RA-Tech mag rubbers?