Take a look at your feedramps and see if they didn't inadvertently stick a rifle barrel extension in your build, causing you to have mismatched feedramps. The side effects of having mismatched feedramps become even worse (failure to feed, deformed bullet tips) if you use steel or aluminum mags (especially without anti-tilt followers) or if you shoot full auto or very fast semi-auto. If your bullet tips look like they're smashed in or cut when you strip the round that failed to feed, this is 90% likely the problem. At your high rate of failure and symptoms you describe of the bullet, I'm willing to bet 100% that this is definitely your problem.
Get a pen or pencil and run the tip from the bottom of the feedramp and push it up into the chamber. If the tip gets caught in the seam, then investigate it further. Does it look like there's a pocket or shelf where the upper receiver and barrel extension meet? If so, then you have mismatched feedramps.
It happens sometimes. One of my Loki rifles had mismatched feedramps. I ended up just using a dremel and a chainsaw sharpening bit to grind out the rifle feedramps into actual m4 feedramps so it would mate with the upper receiver portion of the feedramps properly. Ever since then, the rifle feeds flawlessly, even with the loosest metal mags without anti-tilt followers, hehe.