Extar 5.56 pistol problems?

[Xringshooter]

Anyone have an Extar EXP556 pistol? Are you having any problems with it, especially with failures to feed?
Customer brought one in and it doesn't like to feed rounds all the time, with three different manufacturers magazines. Almost like it doesn't have the required force to strip and feed the rounds reliably. What I'm seeing is the nose of the bullet is hitting the barrel extension cut outs (both sides) and the bolt just doesn't seem to have enough power to force the rounds into the chamber.

Thoughts? Maybe needs a heavier recoil spring is my first thought.

[USMC3531]

I have a gen 1 and never had any issues even with steel cases ammo

[Xringshooter]

He gave me a bunch of ammo (American Eagle 55gr) to test it to see what I come up with. I may try it with a few other brands of ammo also.