Double post

Threaded section of mag catch assembly tip flush with the face of the mag release button?

Pull the mag catch assembly, pull the follower out of the mag, and with the bolt locked home, shove the mag body feed lips tight against the bottom of the carrier, and take a look in the receiver slot mag catch to see just how far up the mag catch slot is against the bottom of the catch slot.  Hence with the mag catch locking the mag on the left hand side, could be that the mag catch is not holding the mag high enough/ the mag loose side to side in the well and dropping down on the right hand side in the receiver, and the reason for the harder angle of attack feed during loading.


Also to point out, the bolt has yet to lock onto the rim of the round, so could be that the extractor spring tension is too strong, or even a bur on the lug face of the bolt or entry area to the extractor taper area not far enough raduis that is not allowing the rim of the round to climb up the bolt lugs and into the  bolt recess/extractor during the angle of attack feed.

Last to come to mind, double check the entry radius taper into the chamber of the barrel.  If the edge is sharp, could be enough that during the angle of attack feed out of the mag into the chamber, the round is self is being scrapped badly, and why the bolt is loosing speed/ not able to fully lock the bolt up as well.

So to sum it up, round will have an angle of attack as it being pushed out of the mag and into the chamber, and now you just need to find out what is the differance from side to side.  My guess, mag drooping down more on the right hand side/increasing the angle of attack, and the problem at hand.