What are the headspace #'s for .303?

[bushwhacker]

I found some headspace gauges in a bunch of stuff that a friend had from the estate of an old gunsmith. There were a .064", .067" and a .074" rim thickness. the rim diameter was .537". I tried them in two different Rifles and the bolts would close on all of them. What are the thickness of the GO, FIELD and NO GO guages for a .303?
Yes, I know this has been discussed before, but I didn't record it.
Bill

 

[bigedp51]

Standard British Military headspace
.064 Minimum
.074 Maximum

American SAAMI standards
.064 GO (minimum)
.067 NO-GO (Maximum)
.070 Field Max

My Enfield headspace gauges below. NOTE: After proof testing with an oiled proof test round the British Enfield bolt must not close on a .067 gauge. (If bolt closed on .067 gauge rifle fails due to excess lug setback)

Canadian Enfield manual for the No.4 Enfield dated 2002 for Canadian Rangers below.

.064 GO
.070 NO-GO
.074 FIELD

British headspace standards from below (.064 and .074)

 

[bushwhacker]

Thanks, I was concerned because the bolt seemed to close with all gauges on a pair of Ross rifles. However, on second thought, there is no easy way to tell if the bolt is completely closed on a straight pull action. I did notice that the bolt didn't seem to catch the extractor properly on the .074" gauge.

 

[cantom]

Thanks, I was concerned because the bolt seemed to close with all gauges on a pair of Ross rifles. However, on second thought, there is no easy way to tell if the bolt is completely closed on a straight pull action. I did notice that the bolt didn't seem to catch the extractor properly on the .074" gauge.

On an Enfield, you have to gently close the bolt with 2 fingers, tap gently down and stop when resistence is encountered.
Compare doing this with no gauge in place and with. The difference is obvious.

The bolt has more than enough leverage to be easy to force closed on the gauge, but don't go there.

I've headspaced a few Rosses, easy enough, get the gauge under the extractor and see how far ahead the bolt can move, then do it without the gauge to compare. Haven't seen one fail yet.

I'm talking .074" Field gauge here.