Hi all,

I have a question about headspace guages. I have read that some guages can be used for multiple calibers if they are based on the same cartridge and have the same shoulder dimensions, such as the 30-06 guage used for checking a 270 Winchester chamber.

I have a 9.3x57 Mauser I feel I need to check. It has a replacement bolt and feels lose compared to my other bolt action rifles, so I want to check it before trying to fire the rifle. If the headspace is excessive I want to rechamber it to 9.3X62, but that is another chapter in the story.

My question is can a 8MM Mauser headspace guage by used to check a 9.3X57 chamber?

Help.

Thanks,
Tom Hughes

I don`t have a drawing of a 9.3x57 to compare with the 8x57 but, if it has a the same headspace to the datum line on the shoulder it should work.

[ 06-17-2003, 01:01: Message edited by: Ol` Joe ]

Tom H. C.I.P.. Dimensions-
9.3 X 57 shoulder angle is 17 1/2 degree'
Base face to shoulder length 1.8035"

8 and 9 X 57 shoulder angle is 19 Deg. 7 1/2 min.
Base face to shoulder length 1.8157"

The 8X and 9 X 57 mm can use the same gages.

For making gages the length to shoulder is given in disregard of the corner radius, the gage being reduced in diameter below the radius once its dimensions are verified. A minimum 8 X 57 m/m gage
would probably protrude .015+ " above the barrel face versus the 9.3 gage. ( IF the 9.3 had not been improperly set up by using the 8 mm gage)
If you can, after removing the firing pin/bolt sleeve assembly, easily close the bolt on a Military 8 X 57 round, then that would be an eyebrow raiser. Ctgs. normally run shorter by about .004 to .006" than the minimum gage. If you can also drop an 8 mm gage in ,same fashion I'd say some fixin' ought be done. IMHO.

Thank you for the responses. I will have to look for the correct guage.

I vaguely remember a headspace check using layers of scotch tape on the bottom of a dummy cartridge, but do not remember how many layers to check with. I will try multiple layers of tape until the bolt won't close on a factory round. I will remove the firing pin assembly as I don't want any booms while doing the check.

Thanks again,
Tom

I was going to recommend shim stock and factory rounds but you seem to have solved the problem tretty well.

Thanks again all. I took out the masking tape and put one layer on a round. I disassembled the bolt and guided the round into the chamber it closed with no resistance. I tried this same procedure with a second rifle and the bolt would not close with the taped round and would close on the untaped one. So it looks like it is a no shoot with my 9.3x57, the first rifle. I put a second layer of tape on the round and tried it again in the 9.3x57 and it was swallowed up too.

I looks like this chamber might have been altered in its past. My next move is to find a gunsmith to rechamber this rifle to 9.3x62 Mauser. I guess that is not such a bad option afterall.

Thanks,
Tom