I just built a .22LR SBR upper for my AR. I used a CMMG 1:16 9" bbl, their stainless .22 kit, an Anderson upper, and a UTG 7" free float bbl. It looks really sharp and is light and handy. But it won't hold a group at all. Last week I tried it with an old red dot I had lying around and got the same results as this week with a new mount and new Leupold scope.
I tried 3 different types of ammo, 2 different mags, and with my Paradigm suppressor, with A2 flash hider, and bare muzzle. All groups acted about the same. First shot, 4-6" or more higher, the subsequent shots lower but in a 4-6" pattern. Can't even really figure out a center for the so-called group.
Reliability was quite good at least.
Where do I start troubleshooting this? I'm thinking to remove and re-torque the bbl but nothing is noticeably loose. I'll call CMMG on Monday to see what they say, but this is always a good place for advice.
So, what should I do to troubleshoot? Ejected live rounds don't show any undo wear or dinging from being chambered.
Thanks,
Bitter Bastard