I recently sold my old AR build (my first build) on NES to fund my new build. My old rifle ran flawlessly. In 5-600 rounds it NEVER had a malfunction. that was mostly with steel cased tula. Myself and a few friends are putting together a few rifles, and while aesthetically different, they are mechanically identical. Two of the rifles are complete and I took mine out yesterday and had an issue with short stroking on certain steel cased ammunition from herters. Today we narrowed it down to just one of the lots of ammo (I ordered 62gr fmj, 55gr fmj, and 62gr hp, and it would short stroke at least once or twice per 20 rounds with the 55gr).
Fine, I even gave a box to someone I saw at HSC of the 55gr stuff, and it seemed to run fine, although I noticed their bolt didn't lock back on the last round. The ammunition also feels underpowered. The 62gr fmj stuff I have runs fine, and any hotter brass loads of I have tried all cycle the rifle perfectly. I should note we are using normal buffers and a mid-length gas system on 14.5 inch barrels (with pinned flash hiders), identical setup to my old AR.
My main concern is at least once per mag a round will hang up during the feeding process. It seems the case neck is getting grabbed by the barrel extension at the top of the feed ramps. The hollow points failed to feed at least 50% of the time, sometimes apprently catching on the front of the magazine, which makes me wonder if the bolt isn't catching the back of the round low enough and possibly causing it to nose dive.
We are using AXTS A-Dac-F ambi bolt catch lowers (superbly machined), Spikes uppers and FA BCGs, and Daniel Defense 14.5 midlength lightweight CHF barrels. I am hoping it is a feed ramp problem but fear it may be a lower problem.
Any insight?
Mike
Fine, I even gave a box to someone I saw at HSC of the 55gr stuff, and it seemed to run fine, although I noticed their bolt didn't lock back on the last round. The ammunition also feels underpowered. The 62gr fmj stuff I have runs fine, and any hotter brass loads of I have tried all cycle the rifle perfectly. I should note we are using normal buffers and a mid-length gas system on 14.5 inch barrels (with pinned flash hiders), identical setup to my old AR.
My main concern is at least once per mag a round will hang up during the feeding process. It seems the case neck is getting grabbed by the barrel extension at the top of the feed ramps. The hollow points failed to feed at least 50% of the time, sometimes apprently catching on the front of the magazine, which makes me wonder if the bolt isn't catching the back of the round low enough and possibly causing it to nose dive.
We are using AXTS A-Dac-F ambi bolt catch lowers (superbly machined), Spikes uppers and FA BCGs, and Daniel Defense 14.5 midlength lightweight CHF barrels. I am hoping it is a feed ramp problem but fear it may be a lower problem.
Any insight?
Mike
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