The 7.92x57JS (aka: 8 mm. Mauser)

This is one of the world's great battle rifle cartridges. It is also an example of how messed-up cartridge names can be.

Before the First World War (Around 1888) the Germans adopted an 8x57mm rifle round. It used a .318" diameter round-nosed bullet. This was commonly called the 8mm Mauser. Shortly prior to WWI (around 1898) they adopted a newer Mauser-designed rifle and a new cartridge along with it. The new cartridge used the then-new spitzer-pointed bullet that had a diameter of .323" -- this caused some confusion! The cartridges were otherwise very similar and you could actually interchange them -- BUT -- if you used the old ammo in the new rifle the accuracy would suffer, but you would be safe and it would shoot. However if you used the new ammo in an old rifle it just might blow up on you. The German arms makers gave the new cartridge a new name. They called it the 7.92x57 IS -- the 'I' for infantry (in German) and 'S' for spitzer (the bullet shape). Enter even more confusion. When printed out in German Gothic script the letter 'I' looks a LOT like the letter 'J' to non-German-speaking folks -- like us Americans. We read it as "8x57 JS" and since we won the war, the name stuck. But both are called 8mm Mauser as well.

American ammunition makers were leery of people with old .318" rifles using the newer .323" ammo (since it was called 8mm Mauser just like the old stuff) so they have always loaded it to lower pressures that it is actually designed for. The lower pressure will keep the old rifles from blowing up if the wrong ammo is used. At least that's the theory. This does reduce the performance of the 7.92x57 JS by quite a bit. If you want full performance you have to get European ammo or load your own.

The 8x57 JS is nearly equal to the American .30-'06 when loaded properly, but the '06 always has a small edge. As a hunting round it is capable of taking just about every game animal in North America. As a home-defense round it IS a bit much, but if you shoot an intruder with a 7.92x57JS that intruder will rethink his current career choice -- at least briefly.

My first centre-fire rifle was a WWII surplus 7.92x57JS Mauser Kar98k. It was the beginning of my reloading experiences as well. Great rifle and great cartridge.

Ammo availability is still pretty good, though military surplus has dried up a lot. You may occasionally find 8x57 JS ammo with headstamps in Hebrew, since Israel used surplus German arms right after WWII -- after all, they were a young country and German arms were cheap at that time. I have always found this ironic.


Home