Could be plastic fouling. I run a bore brush after 5 to 7 shots to get the plastic fouling out when shooting sabots. It usually feels like the bore is getting tight near the muzzle and then loosens up somewhat after 3 to 4 inches. Slides down like normal after that. I can still load with it like that but it does affect accuracy. Trybrushing that outand see if it helps.

Good luck and let us know.

BTW, the 250 SW is a great shooting bullet.