I shoot a lot of 8mm Mauser and I buy as much as I can. I understand 8mm Mauser, 7.92x57mm and 8x57mm are all the same cartridge. But I run into 8mm Mauser JS and 8x57mm JS. What does the JS mean, and how does it apply to the cartridge? Is it a longer casing, or a larger diameter? Would it even chamber in a 1944 k98 (which is my rifle). And would it be safe to shoot out of my rifle? I'm asking because I can't seem to find a source that answers my questions as to the differences. Anyone who could give me an answer or a link to an informative site would be appreciated.
Difference between 8mm Mauser ammo
- Thread starter Prothe2nd
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2damnold4this
New member
The J uses a .318" diameter bullet while the JS uses a .323" diameter bullet. Your 1944 K98 is designed to shoot the .323" JS bullet and should be safe with either so long as it is in proper working order.
The old J .318 ammo was the original 8mm Mauser cartridge and was called Patrone 88 and used in the 1888 Commission Rifle. In the 1903 the larger .323 round was adopted and nearly all commission and K 98 rifles were converted to the larger diameter round and a capital S was prominently marked on top of the receiver to designate the conversion. S stood for spritzer, or pointed, bullet as used in the new round. It is safe, but not very accurate, to fire old .318 rounds thru a .323 bore but not vice versa. I own an unusual unconverted .318 commission rifle built in 1890 by Steyr. It has very few markings and it is a bit of a mystery rifle since I am aware of no military that used the old round after the new one was adopted. I am able to reload with modern 8mm Mauser brass but must use the smaller diameter bullet. In addition, some commercial rifles continued to be built to chamber the original bullet and I believe this caliber was still produced in Europe up until not too long ago and possibly still could be being produced.
Jim Watson
New member
Spell check substitutes "spritzer" for "spitzer ".
I didn't know the jrs cartridge existed until I asked for a box of 8mm Mauser at my local lgs last year and they handed me a box of 8x57 jrs....over the counter, not special order. I didn't notice until I opened the box at home. The 1st clue was a round nose bullet as opposed to the spitzer. 2nd clue was the rim. 3rd and final clue was that it wouldn't chamber. I returned to the LGS and they were kind enough to exchange the ammo for me.
So.....
...like I said, watch out for the 8x57 jrs (rimmed) cartridges.They are, but then again they aren't.
When the 8X57 was introduced, it had a 0.318 bore, and was later changed to .323, and because of this, most of the ammo you can get in the US is crap.
US manufacturers were afraid some dimwit would try and shoot a full power .323 through their .318 bore Gewehr 88 and blow up the gun, and hurt themselves. Europeans figured if you don't know what ammo your gun can safely shoot, you are a moron and deserve whatever happens to you.
Regardless, there are two specifications for what we call 8mm Mauser, the US SAMMI spec "8MM Mauser", which has a max pressure of 35K psi, and the CIP "8x57 IS" which has a max pressure of ~56K psi. To further muddy the waters, "8x57 IS" is often written as "8x57 JS, evidently because the Germans used a Gothic script, and the I looked like a J.
Generally, what you can get in the US is "8MM Mauser", and it the anemic SAMMI spec.
Privi Partisan actually makes both, if you look at their online catalog, they have entries for both "8MM Mauser" and "8x57 IS", with the latter having a higher velocity for the same bullet. For example, the "8x57" IS 198 gr FMJ is 2425 FPS, (essentially the 1934+ military load), but the "8MM Mauser" 198 gr FMJ is only 2180 FPS. Naturally, they only sell the wimpy stuff in the US.
Wolf Gold is made by Privi and loaded to 8x57 IS specs, 196 gr SP @ 2461 fps, but I haven't seen it around in a while.
Remington's and Winchester's only offerings is 170 gr @ 2360fps. Federal's only option is even wimpier 170gr @ 2250 FPS.
These are barely over the velocity as the starting load in my Sierra and Hornady manuals for similar weight bullets.
Hornady and Nosler seem to be the only US folks making "real" 8x57 ammo, Hornady has two options, a 195 hunting bullet and a 196 gr match, both @ 2500 FPS, which is pretty close to the original military load.
Nosler has a 200gr AccuBond or Partition at 2475 fps, and a 180gr Ballistic tip at 2600 FPS, but they are really proud of them, at about $2.50 per round.
Seller & Belot and Norma both make a few 196 loads at ~2600 FPS, but availability is spotty, and while the price on the S&B is decent, the Norma stuff is up in the $2.50/round neighborhood.
FrankenMauser
New member
Had it not been for Gian Giorgio Trissino, the distinction wouldn't matter. Even then... adoption of his suggestion regarding J and I wasn't broadly accepted across the European continent until the mid-1800s (and even later in the states), and the usage had to trickle down from scholars to common literate folk.
For those lost... Between 1524 and 1529, Gian argued for a distinction in the alphabet between the spoken forms of the letter I. Based on his arguments, we got the letter J. (And "Jesus" intead of "Iesus".) ...Also the letter V - formerly combined with U - but that's another subject...
I know of at least two local stores that stock it, as well. It's not recent production ammo, and they're not big stores. They just like to have a little bit of everything, even if it takes 10 years to go through a case of ammo.