Thread: 303 headspace gauge

Originally Posted by Carlsen Highway

A simpler way is to just shoot it, and if you don't get a case head separation, then its fine. I could count the .303's that have matching bolts I have seen on one hand.
Once you've shot all your ammo, then just neck size that brass after that.

You have just stated a classic about the 303's. Most worry about headspace but its nowhere near as big an issue as it seems to be.
I thought I had the dimensions written down or saved somewhere as I was going to make some coin style ones but forgot about it. Not on a lathe in the new job so that aint gonna happen.
This has some info in there and the dimensions seem to pop up frequently so I would suggest are right although 70" seems to pop up as a field gauge dimension also. better descriptions in the link below
https://www.enfield-rifles.com/deter...topic8001.html

GO = 0.064" NO-GO = 0.067" FIELD = 0.074".