I ruined a nice barrel with Bore Butter..
It turned into a hard black glaze in the grooves.
Never again will I use it.. They said I must have used it with some sort of
petroleum based chemical to get this reaction... Nope, Just hot water...
The super tight fit may be because of this buildup beginning in your
rifle also if you have been using Bore Butter.
I have an Optima that is a little difficult (not terribly though) to load after a couple of shots If I do not swab the bore. I swab after every shot. In the field, the first and most important shot
is coming from a clean bore, I practice that way too, Clean bore for every shot.
The XTP bullet you are referring to is what I used this past deer season.
Over 2 - 50 grain 777 pellets. Exit wound was impressive, Range was less than 50
yards.