If you can't get to the gunsmith and don't have a head space gauge set you can use some cellophane tape. Trim the tape to fit on the case head of a new cartridge. Add tape till you get bolt closure resistance, then measure the tape to get an approximate measurement. If it is over .005" the barrel should be setback.
This is assuming there is good new ammo available for the rifle, but it's a wildcat chamber. You can't rely on new brass to be correct without checking, and being Norma brass doesn't carry any water in that department. Heck I'm working through a new box of Lapua 6.5 Grendel brass right now that is .010" shorter headspace than it should be.
