Cousin just bought his dad a 8mm mauser for christmas. It is stamped 7.92mm, my thought is it takes the .318 bullets not the .323's. Supposedly a German gun have not seen it had this conversation on the phone as he wanted me to buy ammo. Told him make damn sure of what you got first.

I know about the J and S stampings but he could not relate the info. Also have no clue as to how old the gun is.

Can you measure the barrel with regular calipers or do you need something special. I was thinking round barrel, square edge of calipers might be enough to throw off the reading by more than the .005 we are trying to measure.

Any other ideas?

M

7.92 is generally the indication of a .323 bore. But, to be sure, go get yourself a soft lead sinker or round ball of slightly larger diameter and with a 5/16 wooden dowel drive it into the muzzle. Then from the breech drive it back out. Measure it with a set of calipers and you will have your answer.

More info about the rifle would be needed to give and sort of pertinent reply as to what you may have.

Regardless, if you buy Rem factory loads you can shoot them through either a .318" or .323" bore with no ill affect. That is why the factory US loadings are so low powered. But, to realize the full potential of the 8x57 with handloads it behooves you to know what bore you truely have. Tell your Cousin's Dad to enjoy the fine rifle he has just acquired.

The military stopped making .318's before the start of WW-1 (and if they were re-arsonaled they got a new tube installed), so the odds of getting a mil-surp in .318 is quite low. Comericials are a little different story, as some makers used .318 barrels longer and they were less likely to be re-barreled.
BTW, 7.9 is the designation for .318, 7.92 is the designation for .323.

Most 8x57 sporting arms built between WWI and WWII had .318 bores. Specifically, if a rifle was built up as an 8x57 sporter between WWI and WWII it technically had to be built in .318 because the WWI surrender treaty forbid Germany from building rifles for the military .323 8x57 round. That did not seem to stop Hitler.

Dave

Thanks, will pass the info along. Don't really know what he wanted it for other than to look at.

M

Surprisingly, I believe there were a lot of customs/commercials made in JS before the war. I have a custom(pretty high grade) with a half octagon, integral rib etc. which was built on a German 88 action, and was completely converted to a Mauser style floorplate/magazine system. It has a 323 barrel and carries the correct JS proof marks. It was obviously built in the period after the JS and new proof marks came out but before the 323 prohibition.

Loud-n-boomer
Actually they simply recut a lot of the chambers to 8x60 and kept the .323 barrels.

BTW, A .323 bullet will go down a .318 barrel with very few problems, due to the time lag between the swadging pressure blip and the main pressure peak. Let's face it, if someone can run a 30-06 round through a 6.5-06 Arasaka with out stressing the rifle (a difference of .044") the paltry .005 difference between the 2 Mauser bullets would be nothing.