I'm working up some loads for a Rem 700 in 300 win mag, but the bolt is chewing big chunks out of the brass, just ahead of the rim (where the normal expansion crease forms on every fired brass) and also the bolt head is filling with brass shavings
Anyway, I think the gun just has some burs that are catching the brass at this point when the case expands, but it definetly get much much worse as pressure increases.
The issue arrises when you try to extract a round. The bolt lifts up easily, but then is nearly impossible to pull back. . . . this is not what is normally refered to as "a stuck bolt" from excessive pressure...is it?
If it is ahead of the rim but behind the belt then likely your extractor claw is doing the gouging. If it doesn't do this on commercial ammo then it is a good sign that your loads are a bit too hot. What do the primers look like?