Had my new 10.5in BRN-180 7.62x39 out to the range today.
I had a issue with the bolt locking back with rounds still in the magazine.
I thought there was a long thread about the 7.62x39 uppers, but its hit the archive I think.
Duramag 20rd mags
Wolf HP ammo
Rugged Radiant suppressor
Gas setting 2
Bolt well lubed
Any ideas as to what to check for?