Threadsmith

Muzzle threading at the lathe. Pick the thread, measure the muzzle, get the number to crank — off the diameter and across the slide, every time.

Make sure it is unloaded before anything goes in the chuck. Action open, bolt out, magazine out, look through the bore. Then chuck on the bore, not the outside: indicate at the muzzle and again an inch and a half in, and support the far end through the headstock with a spider. A thread cut true to the outside of a barrel is not true to anything that matters.

The job tap a common one, or pick from the list

Thread Muzzle OD now — measure it where the thread will be

Bore / groove diameter (optional — checks the wall under the thread)

The setup

Turn the major to (blank = the recommended figure)

Fit

Threading tool

Compound set to

Big number shows

Limits are computed from ASME B1.1 (inch) and ISO 965-1 (metric), and cross-checked in CI against the Thunder Beast Arms thread guide, DWG 14U rev A. Numbers, not advice: you own the setup, the barrel and the trigger pull that follows. Confirm the thread against the device before you cut it.