Problems Getting Upper to Feed Reliably [now with pics]
I purchased a bolt and barrel from reputable manufacturer, Brand X (keeping them anonymous). I assembled an upper half with the Brand X barrel and bolt, a LMT carrier, a Troy gas block, a BCM gas tube, and an unknown brand upper receiver I had laying around. When I tried to hand cycle rounds, the rifle would fail to feed any rounds coming from the right hand side of the magazine. The bolt would fail to go into battery, leaving approximately ½ inch of casing visible in through the ejection port. The round would generally be wedged in there pretty tight. The feed ramps looked good and rounds would slide easily in and out of the chamber when manually inserted. Research indicated that it was most likely an ejector problem.
The manufacturer was contacted and he stated that the ejector was most likely the issue. The bolt was returned. The manufacturer rounded off the edge of the ejector and slightly shortened it. After installing the modified bolt, he upper was able to hand cycle reliably. Unfortunately, once at the range, the upper would fail to eject 2-3 rounds/mag.
So far I have:
-Tried extra lube
-Tried various magazines (somewhat limited on mags in this caliber, but scrounged up a few)
-Tried both LMT and Noveske lowers
-Replaced the ejector with a brand new ejector
-Replaced the extractor with a known good BCM extractor/insert
-Replaced the carrier with a known good BCM carrier
-Removed the gas tube
-Replaced the upper receiver with a known good BCM upper receiver
After doing all of this, I at varying times had the rifle failing to feed from the right side of the magazine only, failing to feed from the left side of the magazine only, and failing to feed from both sides. At no point did it feed reliably. My best result was six rounds in a row.
At this point, I’m starting the think the bolt, barrel extension, or chamber are out of spec/have a tolerance stacking issue (since I've basically replaced every other part). I just wanted to see if anyone had any more ideas before I sent the item back to the manufacturer. I have no doubt that the manufacturer will make it right, but would like to fix the issue myself, if I can. I would provide pictures, but the whole thing is currently disassembled. I can slap it together real quick if pictures are necessary.