This is for a drilling built in the 1930s, so the breech is not cammed via lugs. Can I safely load shells to the same pressures as commercial 8x57 Mauser??
Thanks

No I would not load to European 8X57 JRS levels at all! The 8X57 JR must have it's own pressure level limit and it may even be marked on your barrel.



I have been loading that cartridge for a drilling. All of my loads have been on the light side. This load is quite effective on whitetails within it's range.



Someone asked for such loads and at the time the on line 8X57 IMR data seemed just right for such pressures.



IMR



I use Hornady 32 Special (.321") bullets sized down to .3185".



My loads are a little hotter than the 170 gr loads at the IMR site but are still light. Good powders would be in the 3031, 4064 and 4895 range.

You can safely load it to the kind of pressures/velocities you see in the Lyman Reloading Manual No. 46 or 47 for the 8X57mm - ie., around 35,000-37,000 C.U.P., BUT NO HIGHER! Velocities will be as shown in the manuals. These pressures/velocities are comparable to AMERICAN commercial ammo, but NOT EUROPEAN, which is in the 50K PSI range!



Also, you MAY be able to use .323" bullets. To find out, see if a .323" bullet will freely enter the mouth of a fired case from this rifle before it is resized. If the bullet will easily drop in, you can use .323" bullets. They will swage down to .318", (or whatever your bore diameter is!!) when they leave the cartridge and enter the bore. The key is that the bullet must BE FREELY RELEASED by the case when fired! Oherwise dangerous pressures will result!!



Have you made a chamber cast and slugged the bore? I have a double J.P. Sauer that was an "7.8X57mm" (nominally a ."318") before it was rechambered to 8X60RS, BUT despite being nominally a .318", the bores are and always have been actually .322", AS WERE A GREAT NUMBER OF SO-CALLED "J" BORES!



Good luck!