N E R
If the rifle isn't all cosmolined up, try and get a good look at the bore and muzzle for sharpness of rifling. I always bring a round with me to set in the muzzle. It will provide a good indication of muzzle wear or counter boring. I don't recall hearing of too many MNs having head spacing issues. The rimmed cartridge helps to make this a non-issue FWIR. Good luck!