If you have feeding issues with the Fix rifle first thing to do is purchase the Lancer L7AWM 10 round magazine or the KAC if you can find them. The Lancer mags are about $43.00 but they are worth it. The Pmags simply do not work reliably and should be given to a friend who has a use for them. Run the bolt with authority. If you have tried this and it still doesn't work then something else is wrong. One problem at a time.
The only time I have had heavy bolt lift is when my reloads are too hot. Again you must run the bolt with authority. YMMV
I've diagnosed this ad-nauseum including sending the rifle back to Q only to have the same issues. Asking people to run the bolt with authority works, but just covers up for a design / manufacturing flaw. Extract the rounds you slam in and inspect the tips of the bullets. The real issue is that when a 6.5mm bullet rides up the barrel extension, the centerline of the bullet barely misses the chamfer into the chamber and hits the perpendicular end of the barrel. The chamfer needs the be altered. I plated with the Lancer mag including bending feed lips - no luck.