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Military Firearm Restoration Corner

9.3x62 Case Head Diameter?


montea6b

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My "Cartridges of the World" book has been MIA since the move. What is the case head diameter of this cartridge? More importantly, does it require the bolt face to be opened up like a magnum? How about modifications to the feedrails? Also, what exactly does 9.3mm work out to in inches? Is it equivalent to a .375, or would you need specific metric bullets if you were to reload?

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My "Cartridges of the World" book has been MIA since the move. What is the case head diameter of this cartridge? More importantly, does it require the bolt face to be opened up like a magnum? How about modifications to the feedrails? Also, what exactly does 9.3mm work out to in inches? Is it equivalent to a .375, or would you need specific metric bullets if you were to reload?

 

 

Hi this looks like a standard bolt face to me, as far as feed rails you may have to load a dummy round and try it.

 

Good luck

 

burgie

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Standard boltface, slightly larger case head .006" than .30-06, slightly shorter OAL than -06, bullet diameter is .366". Super cartridge!

 

if I hadn't just spent all my money on a house I would pick up a winchester 1895 at the local gun shop and have it rebored by either dan perdersen or jim dubbell (sp).

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Thanks Burgie! Looks very much like a Whelen as I had heard. I actually was doing a little on-line research in between (as I should have done before posting...) and got the answer on the case head question. I also found that it is .366 caliber.

 

However, I also read a comment that because of the small shoulder it had headspace "issues" like the Whelen. This got me thinking...

 

If the primary danger in excessive headspace is the longitudinal stress on the cartridge causing case rupture, and if a straight walled cartridge does not share this same risk due to having no shoulder for the fore and aft pressure to act against, then it stands to reason that the smaller the shoulder the less the risk associated with excessive headspace.

 

Now, I can see the argument against this logic; for example let's compare a small shouldered cartridge such as a Whelen or 9.3 compared to a large shouldered cartridge such as a .270 WSM. If headspace were .020 over the maximum, and case rupture would occur at .010, then you could make the arguement that both shouldered cartridges would stretch beyond their limit and would rupture. The failure limit of the brass is the same in either case.

 

However, the small shouldered cartridge would have less surface area for the force to act upon and would be less likely to stretch to the full amount allowed by the excessive headspace, would it not? In other words, more of the energy would be expended on the other surface area presented to the expanding gas, (the ass end of the larger diameter bullet) than would be put into expanding the brass, whereas in the .270 WSM the brass would be more likely to be pushed to it's limit.

 

Not suggesting excessive headspace is anything to be made light of or ignored, just thinking theoretically.

 

What do y'all think about that? Am I completely off track?

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Z, I was typing while you posted... A Winchester '95 in a Euro 9.3mm? John Wayne would roll over in his grave! :P

 

I also got to thinking that the shoulder angle would affect the force on the case as well.

 

Additionally, case length comes into play. i.e. if a 12" rope will stretch 1" before breaking, then a 20' rope should stretch 12" before it breaks.

 

So, by my chain of logic each cartridge should have it's own maximum headspace, (beyond optimal that is) and the longer length, smaller shouldered, and shallower shoulder angled cartridges would theoretically have a greater margin of safety in cases where headspace is excessive.

 

I must have too much time on my hands...

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However, I also read a comment that because of the small shoulder it had headspace "issues" like the Whelen. This got me thinking...

 

The headspace issues with the Whelen stem from being chambered in push round feed rifles like the Rem 760 where the shallow shoulder would wedge too far forward in the chamber as the extractor pushed it forward, leaving a "gap" between the case head and bolt face.

 

With a control round feed action you do not have this problem, hence the popularity of a "B grade" Mauser in 9.3x62 in Africa. The claw will keep the case head against the bolt face and all will be well.

 

Jimro

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