Savage muzzle break doesnt fit .

Just bought a new savage fcp-sr 308 and decided to put a muzzle break on it.Came new with a threaded barrel with a thread protector on it.Thought the easy way would be just call savage and order one.They said my thread was 5/8 x 24 and that the one off the model 10-BA would work fine.Came in and seams to be a differant thread pattern.
Just thought someone on here might of ran into the same issue.

Thanks,

Mike

Count the threads in an inch using a scale, or get a thread pitch gauge and measure the treads in/on both pieces to see what it is you be dealin wit.