I have a LMT defender that is having issues short stroking steel cased ammo. The rifle runs fine using brass factory loads. I have been having the short stroking issues with Silver Bear, Brown Bear and Wolf MC ammo (FMJ and HP). I have also tried several different mags (Pmags, L5's and USGI's). I put a lot of brass through this rifle with no issues and was planning to use it for competition but with the round counts so high for these matches it's a big deal on my end not being able to run steel cased ammo.
The rifle will always eject the spent casing and either do one of two things,
-it will go back fully into battery, failing to pick up and chamber and new round resulting in a "click"
-it will push the next round in the magazine a third of the way out and stop with the bolt sitting on top on the round.
I'm guessing this is a gas issue and was thinking of having an adjustable gas block installed by ADCO but I wanted to ask the experts on any problem shooting steps that could be taken to resolve this issue. I have heard that even a slight misalignment of the gas tube can cause SS issues, maybe that's the case? No idea?
The rifle is fairly new with less than 1700 rounds down the pipe, bolt carrier looks good, gas rings are fine and everything feels smooth while hand cycling the action with no binding to speak of. The rifle runs a standard carbine buffer and spring. The ejection pattern is pretty consistent also, ejecting cases to the 3 o'clock - 330 while using steel case.
Before anyone chimes in with "don't shoot junk steel case ammo", this is my main go to AR and I expect it to cycle any ammo I feed it. If my DPMS can cycle steel case without a hitch I would expect my LMT to do the same.
Any suggestions would be much appreciated.