some how two different primmers where loaded om top of each other.I know a guy who used to live in the north east Alabama area, won't say his name. He moved to Kansas for big White tails and started a semi guide business to go with his farming. Anyway, a friend asked to borrow his inline muzzle loader which he gladly did. He even loaded it for him. The guy brought it back after the hunt that nothing was taken,and clyde, not his name took it outside his house to unload it. Put a 209 primer cap on and pulled the trigger. He lost 2 fingers on his left hand from the explosion. The guy he loaned it to also loaded it without telling him. Neither knew it had be loaded other than Clyde the first time, that he failed to tell his friend it was loaded and his friend had failed to tell him he had loaded it. Communication, its a wonderful thing.
Unless I'm reading it wrong Nosler listed 300 WSM at .344" and the 325 wsm at .350" so I figured it's possible. Although I have never tried it.I don't think it is a case of "wrong diameter bullet", because you cannot close a bolt with a .325WSM carteidge in a .300WSM chamber. A .355" case neck will not go into the .342"(ish) chamber neck. Unless you are a gorilla with a sledge hammer.
Storing his rifle on a bench in the barn? Only reason I can think of to have dirt daudbers.Thankfully, You are ok. In all my years of reloading, I had loaded 100 rounds and went to check point of impact. I only used the first round. I never had a reaction like it before and never need another. The gun smoked out of every port. One can never be to careful. After getting home and pulling a bullet, weighing the charge, it was a very obvious the issue. so it was pull 98 more bullets and count my blessings each time.
We all need to run a cleaning rod thru the bore before shooting. Don Lewis, long time writer, for The Pennsylvania Game News, relates in the book he wrote, of the time mud daubers, built a nest in his rifle barrel between his times of using a rifle.
You can kinda see how deep that bore sight was at the end of the barrel. The funny "L" shape near the end of the barrel.Here are two photos of a 7WSM barrel that was fired with the laser bore sighter left in the barrel. Model 70 this was the first round this rifle ever fired by the owner.
Unless upon closing the bolt, the bullet slid back into the caseI don't think it is a case of "wrong diameter bullet", because you cannot close a bolt with a .325WSM carteidge in a .300WSM chamber. A .355" case neck will not go into the .342"(ish) chamber neck. Unless you are a gorilla with a sledge hammer.