Originally Posted by
Serpico1985
Thank you all for the thoughts. There is definitely a burr on the barrel ramp. You can feel it quite easily and catch a bullet nose on it. I suspect that the practice ammo was able to not get caught due to the smaller diameter nose which is why the rifle had zero issues for 300 plus rounds and many different mags. Then when he switched to the duty/HD ammo a problem surfaced in a couple different mags due to the larger diameter bullet nose.
Also, as far as gassing goes, the LMT enhanced carrier and enhanced bolt should prevent any over gassing due to the delayed unlocking and additional gas ports. Do you think the LMT part is enough to under-gas the rifle? Is the Super 42 spring known to be "stout" so to speak. I have A5's on all of my guns so I'm not current on the super 42 info.
We will test with a standard BCG soon.
But here's the question. If we determine that the problem is in fact the barrel extension ramp, how do we fix this? Seems like I could pull the barrel and very lightly sand and then cratex the ramp to eliminate the burr. I've seen School of the American Rifle on youtube do it albeit for a burr in a different location. I have a shop and quite a bit of experience with this type of work from building 1911's. But I know that AR's aren't my lane. Just curious what everyone's thoughts are if the burr is the problem.
Thanks again for your time and thoughts.
Zack
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