Bushmaster had a bad run of barrels, with some of the gas ports being too small, causing what you call short stroking. Have a gun smith enlarge the gas port, or send it back to Bushmaster to be fixed.
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Bushmaster had a bad run of barrels, with some of the gas ports being too small, causing what you call short stroking. Have a gun smith enlarge the gas port, or send it back to Bushmaster to be fixed.
I had this same problem with 2 bushmasters. I replaced the extractor spring and insert with a new spring and a BLACK insert instead of the BLUE. was told to do this by an army marksmanship unit gunsmith and it worked great after that. that is the cheapest place to start. hope it works for you.