Thread: Mauser J Bore
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Old April 26, 2005, 07:25 AM   #2
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Join Date: April 3, 2005
Location: Rochester, New York
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It appears you have a 8mm of the earlier type with a .318 bore and it was designated as a "J" type. The Germans later switches to the "S" bore that measured .323. The cases are the same other than the neck being changed to accomodate the newer bullet (.323). You can fire the older (J) ammo in the .323 rifle, with the resulting loss of accuracy but not the reverse. You should have no trouble using the current cases other than having to reduce/expand the neck and locating .318 bullets. There should be load info around on the net. I don't know the rifling twist but the older J bore shot a 226 gr. round nose and the newer S shot a 154 gr. bullet so there may be a difference in twist that might affect accuracy. You obviously have some homework if you want to shoot the gun, but it is a fine cartridge and right up there with the 30-06. Good Luck
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