War Baby: The 8x68S
By Chuck Hawks
1940 was the year that the 8x68S was introduced by RWS in Germany. Other events in Germany and Europe that year commanded the world's attention, and the birth of this powerful new hunting cartridge intended for bolt action rifles was generally overlooked by sportsmen outside of Germany.
It wasn't until after the end of the Second World War and a return to normalcy in Europe that the 8x68S began to attract the attention of European sportsmen and hunters. Unfortunately, it remains largely unknown in North America.
The cartridge is based on a large, non-belted magnum case 2.658 inches in length. The rim diameter is .512 inches, larger than the standard non-magnum rim diameter of the 8x57JS or .30-06, but slightly smaller than the rim diameter of standard belted magnum cases like the .300 Win. Mag. or .375 H&H. 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, somewhat less than the 17.5 degree shoulder of the .30-06 and much less than the 25 degree shoulder angle of the 8mm Rem. Mag. or .338 Win. Mag. The maximum cartridge overall length is 3.425 inches, so the heaviest bullets are seated pretty deep in the case.
This case gives the 8x68S a slightly disjointed look, a fat, large capacity, modern looking magnum case with the relatively sloping shoulder of a much older cartridge. Perhaps this is inevitable when you consider when it was designed, sort of in-between the standard cartridges of the pre-war era and the post war magnums.
The Norma and RWS web pages offer ballistic information about 8x68S factory loads. Norma info calls for a MV of 2953 fps and 3874 ft. lbs. ME, this with a 200 grain Swift A-Frame bullet. The 300 yard velocity is 2211 fps and remaining energy 2171 ft. lbs.
The Hornady Handbook of Cartridge Reloading includes the 8x68S and North American shooters with a pet 8x68S rifle will very likely want to reload for it, so the ballistic data that follows is taken from that source. The Hornady technicians used RWS cases and Federal primers in a Mauser 66 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.
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. This would make a flat shooting load for CXP2 class game, what I would consider a 300 yard pronghorn antelope load.
The Hornady 170 grain Round Nose bullet 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. A round nose bullet does not seem to be the best choice for most purposes in the 8x68S, and this one is intended for use in the 8x57 cartridge, although it should make a good brush load for CXP2 class game at reduced velocity. 64.3 grains of IMR 4350 will give a MV of 2700 fps.
Curiously, the latest Hornady Manual (the 7th Edition as I write this) does not list loads for their 195 grain Interlock Spire Point, which would probably be the best all-around bullet weight for the 8x68S. However, with some careful experimentation it should be possible to drive this bullet at velocities between 2500 and 2900 fps. The BC of this bullet is .410, which is quite favorable. At about 2800 fps this would seem to be a good choice for mixed bag (CXP2 and CXP3 class game) hunts.
The 220 grain Hornady Spire Point bullet was designed for the 8mm Rem. Mag. It can be driven to a MV of 2500 fps with 65.0 grains of MRP powder, or 2800 fps with 71.8 grains of MRP. The latter is only 100 fps below the top load listed for the 8mm Rem. Mag. It develops 3831 ft. lbs. of ME and is obviously a very potent load, suitable for the largest North American big game. Except for thick skinned dangerous game, this load should be adequate for any large game in the world.
The trajectory of this bullet is such that at a MV of 2700-2800 fps you could zero a scoped rifle at 200 yards and have the bullet hit about 2 inches high at 100 yards and about 8.5 inches low at 300 yards. That means a point blank range of at least 250+ yards.
One of my Canadian correspondents, Gord Shepard, who uses the 8x68S contributed these impressions of the available bullets: "In my opinion the smaller 8mm bullets were designed to be fired out of lower velocity firearms such as the 8mm Mauser. They don't stand up to the kind of energy which this cartridge can deliver, which impairs performance on game. However the larger bullets such as the factory 187 grain and 196 grain bullets, plus the 220 grain Hornady and 220 grain Sierra are tougher bullets which were designed for the magnum velocity and energy which the 8x68S and 8mm Rem. Magnum can deliver. I have shot whitetails and moose with the 220 grain Sierra, and it performed superbly, both in terms of accuracy and terminal effect. Plus the heavy boattail takes full advantage of the long range accuracy, trajectory and knockdown power which sets this cartridge apart from lesser calibers."
The only real drawback to the 8x68S is that, like any similar size magnum rifle cartridge, it kicks pretty hard. At around 30 ft. lbs. of recoil energy in an 8.5 pound rifle, the recoil is comparable to that of a .300 or .338 Magnum. In summation, the 8x68S is a fine European big game cartridge that would be a good choice for hunting in Alaska, Asia, Africa, or anywhere else.
Copyright 2002, 2012 by Chuck Hawks. All rights reserved.