Part 2 - (read Part 1 first - https://www.builderstribe.org//forum/ar-platform/my-new-cmmg-conversion-kit-part-1 )
OK so here is where the hiccup happened. When loading the first full 25 round mag I consistently experienced failure to feeds when using the charging handle.
So I loaded one round in the chamber with one mag then put in a full mag. It ran all 26 rounds flawlessly. Weird.
After testing to see how many rounds I could load in a mag before experiencing the failure to feed (11 rounds), I ran the remaining rounds allotted for today, minus the damaged rounds from the failures to feed (see below).
In conclusion, it seems that the spring tension could be the cause of the problem. I'm contemplating polishing the feed ramp since I don't have time to get a replacement before Saturday. Ugh! I'm open to suggestions guys.
I've had a similar problem before, but don't remember the fix. No help, I know.
Definitely won't hurt to polish the feed ramp. Should do that anyway.
Try some different ammo. Minimags are good, and my go-to, but wouldn't hurt to troubleshoot with something different.
Try a different magazine.
You may have to tweak and polish the mag feed lips a bit. Sounds like the magazine spring tension is a little too strong for a low-inertia feed from the charging handle/bolt release.