Concentricity

[Phantom30]

My opinion is that the feed ramp edges or corners mostly scratch the brass, at the neck and or the shoulder.  A de-bur/polish of the sharp spots can fix the problem.
Chamber a new made dummy round or if safety permits a live round and eject w/o firing and inspect and evaluate.  parallel marks about the width of the feed ramps are likely sharp corners that need work.
If the bullet is free from damage I would think case scaring would not make your groups much bigger, but you want to fix it to prolong case life.

What I am talking about is the leverage induced on the seating alignment when chambering.  The tip of the bullet contacts the barrel extension while the base is still held by the magazine.  This torque effect can slightly change the alignment creating inaccuracy.  My powder coated bullets are more effected than standard FMJ.  They are seated at the base of the neck and with a gas check on the bullet that part becomes a pivot point for changing alignment versus the softer PC on the rest of the drive band.  The other effect is impact for a soft bullet tip.  Clearly using an SP round will open the MOA because of imbalance cause by denting the tip on chambering impact.  Both are driven by the barrel extension that's why the comparison.  I would shoot more to make a more consistent comparison but these effects are also exhibited in 6mm and 6.5mm Creedmoors.  All three are to expensive to waste anymore.