Discussion in 'Center Fire' started by ClintG, Apr 7, 2005.

  1. ClintG

    ClintG Member

    I have a question about a rifle that is marked for 8x57J ammo.

    I can find 8x57 and 8x57JS. What does the J mean? Is JS the same or will just plane old 8x57 work? The 8x57 is around $20 a box and the 8x57JS is around $40 a box, so there must be some difference.

    Thanks for any help, Clint
  2. uglydog

    uglydog Super Member

    I beleive the 8x57J was the first version of this round and was made in the early Mauser rifles. It had a bore diameter of .318". Later the designation was changed to the 8x57 JS where the bore diameter was increased to .323" and the cartridge loaded to higher pressures. It is considered rather unsafe to shoot the "JS" ammo in the "J" bores as dangerous pressures can result. One needs to know the bore size to get the proper, and safe, ammo. European 8x57JS ammo is loaded to much higher pressures and would be very unsafe to shoot in an 8x57J gun. The U.S. manufactured 8x57 ammo is loaded to such low pressures it "SHOULD" be safe to use in the old Mausers but the guns are of such varied construction with "mix and match" parts (especially the very inexpensive surplus guns that are hitting the market) that the gun should be checked for headspace, soundness, and parts compatability by a qualified gunsmith before use.