I have it in my mind I want to ultimately have an ar9 sbr, then add a can. Prefer it to take glock mags. I’m rather overwhelmed by the number of options (blow back vs piston, which assist type) and don’t know what would work best for an ar 9 pistol to start with. Or, would it be better to just go with a 300 blackout? I blame rustyzx9 for wanting a sbr 9mm with a can. His was fun to play with.