What ammo? Is his tri lug machined into the barrel or one of the screw on mounts? I'm assuming that the can/mount lockup feels solid or he wouldn't have sent anything.

I have a GHM 9 with a 8.9" barrel machined in tri lug, and anything thats not FMJ/TMJ is terribly inaccurate (e.g. plated). Foot + groups at 25 yards. Huxwrx Rad 9. I stick to 124gr or heavier Federal FMJ/TMJ/JHP.