ROSS MK111-You guys are just too slow on the trigger.

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b72471

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Some of you will recall a pretty little ROSS with a very nice tiger stripped stock beatifull wood, 20" barrel. The seller stated there was a head space issue, being a rimmed cartridge I wondered about that and took the chance. Today I cleaned up the rifle place a shell in the chamber and all looked OK. So I stepped out back and fire a test round, I had measurements before and after of the brass, lenght expanded .001, just above the web dia exp .003, at the shoulder dia exp.006. GOOD TO GO.
Enjoy
 
b72471 said:
Some of you will recall a pretty little ROSS with a very nice tiger stripped stock beatifull wood, 20" barrel. The seller stated there was a head space issue, being a rimmed cartridge I wondered about that and took the chance. Today I cleaned up the rifle place a shell in the chamber and all looked OK. So I stepped out back and fire a test round, I had measurements before and after of the brass, lenght expanded .001, just above the web dia exp .003, at the shoulder dia exp.006. GOOD TO GO.
Enjoy
Click to expand...

Part of the "headspace problem" is that the Ross was chambered for the .303 cartridge dimensions of the time. The rim was a bit thicker than a lot of the present day commercial loadings, so this creates extra headspace. Use a small rubber band or better still, a small "O" ring for the first firing as that will hold the base of the cartridge back against the bolt face. Then, neck size your reloads, and you are good.
 
Apparently Ross had some amazing tool for measuring headspace. Not having that, I've used my Field gauges to do so with success.

Ease the bolt forward and observe how far the bolt is rotating into full lockup. Observe the difference between no gauge at all, and with your headspace gauge in place. Ease forward while observing is the operative word, not slam forward. Needless to say, that is with the gauge rim under the extractor just like a cartridge.

As long as the bolt doesn't go as far into battery/full lockup with the gauge as without, that appears to be a reasonable facsimile of passing headspace no? What you want is resistance before going fully into battery.
 
A small note on that. Use VERY LIGHT finger pressure when moving the bolt forward. ANY resistance is enough! It is possible to close the bolt if you try hard enough!!!!!!!!!!!!
 
Military Spec on the ammunition was for a Rim with a Max thickness of .063", going into a rifle with a Minimum rim clearance (headspace) of .064".

MUCH modern ammunition is made with THINNER rims, which will automatically give you extra "headspace".

That is why the O-ring (or pony-tail tie) is a REALLY GOOD idea: it forces the cartridge back against the bolt-face, reducing headspace to an effective ZERO.

When the round is fired there is NO extra thinning of the critical WEB of the cartridge and all expansion is at the FRONT. The result is brass which is perfectly fire-formed to THAT rifle.

This is the FIRST STEP toward producing ACCURATE ammunition for that rifle.
 
If the bolt closes fully over the GO and doesn't close over the NO-GO then you're good to go. How bout that eh? ;)

Photos? Price?
 
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