I've done some research, and while large vs small shank / thread pitch specs are everywhere, I'm not finding much for what the LENGTH of those threads up the shank should be. I've seen both 1.600 and 1.550. This says 42.06 mm, which would be 1.655.


I'm having a problem headspacing a new custom barrel for a Savage Impulse. I have the barrel nut back as far as it will go (ran out of threads), and when the barrel is threaded into the receiver to where the nut hits, I still have about .020 headspace, which is clearly no good. I got to measuring the length of the threads (from breech to last thread), and the custom barrels are shorter.
2 Savage factory barrels: ~1.600
3 Custom (same manufacturer): ~ 1.550



Are my custom barrels just not threaded to spec, or is something else off?