I was resizing some 6.5 creedmoor and 300 Win Mag brass last night. The 6.5 dies are brand new. The brass is Starline brass bought new and fired once. The initial resizing was nothing more than me making sure the case mouths were round. The 300 WM brass was bought new from Gunwerks and has been fired 1 or 2 times. I’ve been using the 300 dies for over 30 years. For some reason last night it took an extreme amount of force to resize the brass. I was using the same lube and procedure I’ve used for years. I thought I was going to break the bench. I polished the expander on the new die and cleaned the die but it did not help. Never had to use this kind of force. The only thing different is the brass for the 300. The brass and the die are new for the 6.5. Can different brands of brass be more difficult than others to resize? I’ve never used either of these brands before. It was a workout to do a few pieces. Any thoughts would be appreciated.