That crown is from a Remington. I was given the task of getting a load done for a guy and it was left to me to get the rifle up to snuff. It was a 300 Win Mag and it shot IMR4350 and 150 Nosler Accubonds into a .6xx" group.
Tiny, I bought a NECO Fire Lapping kit many moons ago and couldn`t bring myself to run the coated bullets down the bore. I used the kit along with a bronze ball ended muzzle lap from Brownells. I ordered the one without handle and chuck it in a Dewalt drill and run it slow in a circular motion. I own 3 of those muzzle laps and can polish from .22 to .50 caliber bores.