i shot 60rds of federal 55gr BST out of my 22-250, then the 40rd box of UMC 50gr JHP ammo...then got 3 more boxes of the federals. different lot than the first 3. first round i fired pretty much locked the bolt. it was STIFF. it was a bit hotter out that day...maybe 10-15 degrees. someone else said maybe solvent in the chamber...they could been right on. hotter temps outside also add pressure though...most factory ammo is loaded under the max and safe though..i am betting solvent in the action/chamber..i cleaned it right before i went to the range and was in a bit of a hurry....

checked the case and it was fine..not bulged or cracked or blown primer or anything...checked the action and barrel and all looked well. fired the rest of the box with no troubles....