Not in a blow-back gun, like most 9mm ARs, which it sounds like what the OP is shooting as he's talking about buffers, etc. The buffer/bolt has to have enough mass to hold the action closed while pressure dies off... keeping the action closed (it never "locks") is exactly it's job. too light and the rounds extract too early.
as excessive as these are, I would also assume firing OOB vs early extraction as others said. Assume using a heavier pistol buffer vs regular carbine buffer? I would look closely at belling/crimp and make sure bullet diameter is .356 max unless you've slugged your barrel. 9mm being slightly tapered, a wide mouth could lead to it only mostly seating. I would also check seat depth consistency / bullet shape... anything that could keep a round from feeding all the way. plunk test 100 rounds into your barrel and see if the problem persists...
bolt bounce can be a problem too. make sure buffer has dead weights that are free to move. that is where a too-light spring could also lead to this result.
-rvb
an AR-10 in 300 WSM would definitely not be a pistol or a straight blow-back action. Different buffers and buffer springs definitely have different results in your typical AR-15/AR-10 rifles. Otherwise there wouldn’t be so many choices.