From my experience with the rifles that seem to not like the norc ammo specifically... It's a spring thing or a gas thing. That's assuming no other issues like binding ect.
Not enough gas flow or too much oprod spring tension. Both of these can cause the rifle to short stroke. Some do it consitantly and some it's a hit n miss where a few rounds fire and then a fail to feed.
Problem is bolt not going back far enough to pick up the round.
OR
It picks up the next round but fails to eject. This is also a "not enough recoil" thing. The bolt has slowed down enough that while it chambers the round, the bolt has lost the inertia need to pop the extractor over the case rim.
So, all you can really do is verify gas system function by the piston drop test (we wanna see some vacuum)
Verify optimum gas port alignment with a 1/16 drill rod or similar item. Stick it into little hole bottom of gas system , with piston removed, and the rod should pass clear into barrel.
Verify rifle is properly greased and is not physically binding with bolt/oprod
Try it with factory spring and guide rod.
If all the above checks out and she still has a problem. We need to look at gas volume and dwell time. These are best left to experienced hands.