8mmx57 vs 8mmx57JS

Bob Green

I just picked up 2 inexpensive Turkish Mausers to restore. While reading up on another website about testing the bore and headspace, the author noted that his 1903 model was a 8mmx57JS and his set of 8mm gauges would not work. Is there any way to identify between the 8mm and 8mmJS?

I have;
1903/1944 K.Kale
1893/1936 ASFA ANKAR

Wehrmacht_45

There are two 8x57 Rimless Mauser cartridges. The early 8mm has a .318 bore, and was used from 1888-1905 and is usually called the 8x57j. In 1905 the cartridge was updated with a spitzer point, a .323 diameter bullet, and the grain weight was cut to increase ballistic coefficient.

I am willing to bet yours are more than likely what we think of as the Standard 8mm Mauser, the .323 bore. A gunsmith could easily confirm this, but the latter dates on your rifles would lead me to believe that even if they were made originally for the 318 ammo, they would have been converted for the sake of standardization when re arsenaled in the 30's and 40's.

jonk

In 1888 with the adoption of the Gewehr 1888, the Germans also adopted a new Mauser-designed cartridge, the 7.9X57i. This bullet measured .318" in diameter, I standing for "Infanterie" or infantry. Logical enough. However US guys, seeing these guns, and the ammo in packets for them, did not know that in the old style gothic, fractal script the Germans favored at the time, they were looking at an 'i' and thought it to be a 'j'. Hence the long misnomer 'J-bore' when it should be "I".

So things were hunky-dory but around the turn of the century, very high speed spark gap photography was invented, and ballisticians realized that a round nose bullet was not optimum- and the 7.9X57I was a round nose bullet. So they re-designed the round to a pointed, or in german, "spitzgeschoss" or pointed bullet. Right? At the same time, also for ballistic calculation reasons, they increased the diameter of the bullet from .318 to .323. The same basic case was retained, just bullet diameter was increased by 5 thousandths of an inch. The new round was called the 7.92X57IS- or Infanterie, Spitzgeschoss. This fired a 154 gr pointed bullet of .323 diameter. Finally a 7.92X57IsS was invented, or schweres Spitzgeschoss "Heavy pointed bullet" of 198 gr, which was what would be used in machine guns in later WW1 and in all guns of WW2.

The 2 guns you have- well you would need to slug the bores to be sure. However I would also very much think that they are both .323 if not larger- loose military tolerances- due to their rework dates. The 1893 started life in 7.65X53.5 Mauser and was rebarreled by the turks. The 1903 might have been made for the original I bore loading but if reworked in 44, again, no issue; plus it is a 98 action and even IF the bore is a tad tight, the throat almost certainly isn't and it would swage down the bullet just fine.

The problems come if someone fires, repeatedly, full power military loads of the .323 bullets down a Gew 88 bore, with its mannlicher bolt head, lack of gas venting, small recoil lug, and on some models, thin barrel. Then you can damage the gun. But for those guns, you should be fine.

Do note however the 93 action is not a terribly strong one. Yes it can fire the 8mm round just fine but don't go re-barreling it to something bigger, and I wouldn't feed it a steady diet of max 8mm loads either.

MIKE WISKEY

"the author noted that his 1903 model was a 8mmx57JS and his set of 8mm gauges would not work."............the headspace on both the 8x57I and 8x57JS are identical, and h.s. guages will work in either. Just the bullet dia. is different.

nononsense

Bob Green,

Welcome to the Gunbroker Forums!

"the author noted that his 1903 model was a 8mmx57JS and his set of 8mm gauges would not work."

If this is truly how it was written, chalk that statement up to an Internet Wannabe that doesn't know what he's talking about. Mike Wiskey states it correctly, the headspace gauges are exactly the same. It's the throat design and the groove diameter of the barrels that is different.

As noted and suggested again, please take the time to either slug the barrel with soft lead or cast the chamber, leade, throat and a short length of bore with Cerrosafe which is available through Brownells. The lead slug can be measured to determine both the land and groove diameters. The casting will give you a record of the chamber dimensions as well as letting you measure the lands and groove diameters.

Enjoy your new hobby!

Best.

Bob Green

Thanks for everyones help.

I searched for a Slug Kit and found one on the internet. They wanted $40 and I believe it was only good for 2 rifles. Then, add in the cost for calipers to measure the slug.

So, I went back to "surplusrifle.com" and found an article on Slugging. Headed to Wal*Mart for fishing lead sinkers and a wooden dowel. Cost...about $2.50 and enough sinkers for 10 rifles. Works out to about .25 cents per gun. Of course you do need the caliper but thats a good one time investment if your playing around much with this stuff. I found one at Lowes. They start at $11 and up. I found a nice digital display SAE/METRIC with case for $30.

Works great. tested the K.Kale and its a perfect .323 with a bore diameter of 7.925.

Thanks again for all the help.

nononsense

Bob Green,

Congratulations on your research!

Thank you for following up with the forums concerning this project. Frequently we get left hanging, not knowing how things turn out. I appreciate your effort to report back.

Best.