In 07 or 08 Bushmaster was acquired by Cerebus Holdings. Since then QC has slipped. When I worked at the shop late model Bushys were one of the most frequently brought in with issues.
Stupid stuff like loose pistol grips, 2 gas rings instead of 3, missing buffer detents, missing safety detents, weak staking of the gas key causing it to loosen, loose buffer tubes and such.
Just poor quality control.
Bushmaster is actually shutting down operations and moving to one of the Carolinas IIRC.
Too bad, they were great rifles.
My Colts have been flawless as well.