8x57 IR

Does anyone know much about this round. Is it the same as the 8x57 IRS ?

Is it .323 or .318 ?

Are loading dies & brass available?

Ballistics and loading data?

Any information would be of great help.

Thanks.

Tim

"R" indicates a rimmed version of the cartridge.
"S" indicates a bullet diameter of .323".
"J" and "I" are often interchanged with each other.

Well, you have to understand that it is a German cartridge and that the cartridge has a long history, not always consistent with good understanding.

8mm J. J is the German I and is used in other languages alot that way. So 8x57I = 8x57J. J(or I) stands for infantry, whatever the correct German is for that word.

R is the metric designation for a Rimmed case. So 8 x 57J is rimless and 8 x 57JR is the same cartridge with a rim added.

Metric designation uses bore size for the first number, not groove size.

8mm is a generic size and started with 0.318" bullets. That is not the bore size, the number is the groove size/bullet size. If you figure out an 8mm bore (remember bore size is used in metric designation for caliber, not groove size) it should be 0.31496 inches, an improbable number, given the 0.318 groove number. That is why 8x57J, the first 8mm is also designated 7.9 x 57 or 7,9 x 57J. That 7.9 mm number figures out to be 0.311023 inches, a more reasonable bore diameter for the 0.318" bullet.

Progress comes along. Now, the German military discovers that sharp-nosed bullets are better at flying and that higher pressure gets higher velocity. To prevent the new sharp nosed bullet with its higher pressure ammo from being used in the older guns, it get a new diameter, a new designation, a new shape, and more pressure, all in one fell swoop. The new 8 x 57 mm round becomes 8 x 57 JS, where J=infantry and S=spitzer (spitzer is an interesting word, by the way). The new hole down the barrel is opened up to a groove diameter of 0.323" and the bore is opened up just a little to go with it. The new bore is now stamped 7.92mm and is about 0.3118 inches or call it 0.312 inches. Not enough to brag about, you see, but the barrels can be stamped differently and are put on actions capable of handling more pressure. The new cartridge becomes known as the 7.92 x 57 mm or 7,92 x 57JS mm or 8 x 57 mm JS.

In time there is a double rifle chambered for the rimmed version of the new 8mm and it becomes 8 x 57JRS or 7.92 x 57JRS and shoots the same 0.323 inch bullet.

Now we have:
8 x 57J, 7.9 x 57J, 8 x 57JR, and 7.9 x 57JR. Actually the J and JR on the 7.9 designations are redundant, but who really cares with this much going on. All of these shoot the 0.318" bullet.

We also have 8 x 57JS, 7.9 x 57JRS, 7.92 x 57JS, and an7.92 x 57JRS, all of which shoot at higher pressure and shoot a bullet that measures 0.323 inches.

Your 8 x 57IR is actually an 8 x 57 JR/7.9 x 57mmJR rimmed cartridge that operates at the old lower pressure and should shoot a bullet about 0.318 inches in diameter. It is just that someone transliterated the J as an I and stamped it so. Occasionally German guns will do this, too.

Slug your bore and make sure that you actually have 0.318" grooves and use the correct bullet for the groove diameter. Tolerances were very sloppy by today's standards. Just remember to load to the lower pressures suited to the older cartridge.

Hope that helps.