My friend has a problem with his LMT 10.5" we just built. It will either fail to feed a round off the magazine or partially feed one, resulting in a jam, about every other round. It seems to do so only when feeding rounds from the right side of the magazine. I've tried it with USGI and Pmags and the results were the same. It also fails to lock back on an empty mag.
He is running a LMT 10.5" upper with LMT M16 BCG, A2 FH, MilSpec M4 buffer tube, stock buffer spring, and H buffer.
We were at the range and I took apart the buffer and removed the tungsten weight. We ran it with just the two steel weights and the problem was the same.
I'm guessing that LMT's are under-gassed. I built a 14.5" using an LMT upper for another friend and his would only run with a carbine buffer on an M16 BCG.
I'm thinking of getting a Wolff reduced power buffer spring for my friend's 10.5" and a standard carbine buffer. I'm hoping that will fix the problem. I'm also considering removing all the weights from his buffer and seeing if it will work with the stock spring and super-light buffer.
Is this a common problem with LMT uppers?
I built myself an 11.5" with a Sabre Defense barrel, A2 FH, on a CMT upper, LMT M16 BCG and it runs like a clock with a standard spring and H3 buffer.


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