I would ask what action are you using
Ihad that happen on a sav 14 action that I got in 308
The factory at sav seems to gall some the thread on some from time to time
I had a real hard time geting the barrel off and upon looking at it, it seemed to have boogerd threads. I did manage to get The replacement barrel on, but it was a hard screw
I am sure it was a defect caused by savage at the factory- am equally sure yours us same. Never seen an after market missthreaded