Here's what I did. Loading 300 WSM for a Browning X-bolt using once fired Winchester brass from this gun. All brass full length sized and trimmed. After priming and charging, while setting up the seater die, I screwed the die in til it touched the case mouth. I then mistakenly screwed the die in one full turn rather than backing it out 1 full turn. This gave me a heavy crimp and also smashed the shoulder slightly. The cases would not chamber. I pulled the bullets and full length sized again. The cases are now very tight in the chamber with some being very difficult to close the bolt on. Should I force the bolt shut and shoot em to fireform back to shape?

Did that. Actually I kept screwing it in about an 1/8 turn per try until I had it screwed in a half a turn beyond touching the shell holder.

+1...............

My initial thoughts were to toss em as I also had 45 pieces of once fired federal brass. I sized and trimmed those but gave up on em when the primer pockets were loose. That's when I decided to try to resize the Winchesters. The bolt is very tight on some needing a tap from a rubber mallet to open after being forced shut. Think I'm gonna toss em and order some new brass.

Nope, the federal cases I had were nickel. But after searching Midway, MidSouth, Natchez, Sinclaire and Cabelas, no WSM brass to be found. Gonna have to wait on load development til I can get my paws on the cases.

Just tried those 3. Grafs and Cheaper than dirt have none, 3rd Gen has some Norma, 25 pieces for $50........ouch. Think I'll see if a couple of local shops can track down some Winchester or Remmy for me.

There is some on gunbroker but they aren't giving them away.
Check your local Craigslist too. I see 300 WSM on there from time to time.