The 8x68S RWS
By Chuck Hawks
Unfortunately, the 8x68S remains largely unknown in North America, although it is popular in Europe. The cartridge is based on a large, non-belted magnum case 2.658 inches in length. The rim diameter is .512 inches. The 8x68S has a rebated rim, since the body diameter just forward of the extractor groove measures a fat .524 inch. The shoulder angle is just over 14.5 degrees. The maximum cartridge overall length is 3.38 inches, so the heaviest 8mm bullets are seated pretty deep in the case. Bullet diameter is .323".
Fortunately, the sixth edition of the Hornady Handbook of Cartridge Reloading includes the 8x68S, so all of the ballistic data that follows is taken from that source. 71.0 grains of H450 can drive a 150 grain Hornady Spire Point bullet to a muzzle velocity (MV) of 2900 fps, and 82.4 grains of H450 can drive the same bullet to a MV of 3300 fps. Muzzle energy at the latter velocity would be 3628 ft. lbs.
63.8 grains of IMR 4350 powder will give a MV of 2700 fps with the Hornady 170 grain Round Nose bullet. This projectile can be driven to a MV of 3100 fps and ME of 3629 ft. lbs. with a maximum load of 72.1 grains of IMR 4350 powder.
The 220 grain Hornady Spire Point bullet can be driven to a MV of 2400 fps with 58.5 grains of IMR 4350 powder, or 2700 fps by 64.7 grains of IMR 4350. Except for thick skinned dangerous game, this load should be adequate for any large game in the world.
The Hornady technicians used RWS cases and Federal 215 primers in a Mauser 66 rifle with a 26 inch barrel for testing. In general, the performance of the 8x68S is close to what you would get if you necked a .338 Win. Mag. case down to accept standard 8mm (.323 inch) bullets.
Note: A full length article about the 8x68S can be found on the Rifle Cartridge Page.
Copyright 2005, 2013 by Chuck Hawks. All rights reserved.