My 14.5 Mid-length doesn't like 55gr.
I have a Sabre Defence 14.5" 1/7 with the 9" mid-length gas system. I'm running a stock (from the factory) buffer assembly.
Today I took it to the range and it consistantly had failure to extract, failure to extract combined with partial feed, double feeds, and also the occasional empty casing shoved forward into the leading edge of the ejector port. Out of several magazines maybe only 3 times did I get more than 1 round to fire without a jam of some type. It appeared the bolt carrier assembly wasn't being pushed back enough to extract the round and feed the next...short-stroking for lack of a better phrase.
So, we had other AR's and extra parts (and being able to swap things out) available of all sorts.
Basically turning into some type of science experiment, and through the process of elimination, we were able to rule out extractor and spring since it was not extracting. Ruled out the magazines. Ruled out different brands of ammo. Then we decided to try out a few rounds of the expensive stuff, Hornady TAP NATO 75gr. 5.56 that I had brought to the range just to try out.
The 75gr TAP was the only thing we could get to feed flawlessly. I don't know why, or how, or what...but that's it.
Anybody else have the same set-up and running 55gr rounds without issue? I wanted something I could shoot 55gr through as well as the heavier stuff.