I'm wondering, how much difference is there between GO and NO-GO gauges for the 30-06? Is it different for different calibers? I've never bought a NO-GO so I don't have any to measure. Thanks.

Clymer Reamer Co. will have all the dimensions for most headspace problems. I have made some headspace gages and Clymer is the only company that would give the datum line diameter needed to make certain measurements. I have used their gages and reamers for many years. Now for the 3006 the normal no-go is too long to suit me. I prefer to have my chambers very close to the go gage. Military rifles will take chambers up to different standard than the normal custom fitted barrel.

I'm looking at a set of ordnance gages I have used for 50 yrs and they are marked 1.940,1.946,1.950 which I think were the go nogo and field gages in use by Army ordnance at the time.

The No go is .006" over the go gage and the field is .004" over the no-go.

.004 to .006 depending on maker, with .005 the standard

jeffe