of the bullet of the new round was .005 inch smaller than the Lebel, or .318 inch. Unlike
the fat, rimmed Lebel, the German case was narrower with no protruding rim. Instead the rim (obviously
necessary for extraction of fired cases) was the same diameter as the case body above the
rim. A recess for the extractor was machined into the case, thus forming the rim. Also,
the case was bottle-shaped (larger diameter body that tapered down to hold the bullet by
way of an angled shoulder) like the Lebel. Having no rim, however, the new case headspaced
on the shoulder. Case length was 57mm. The new round was designated 7.9mm Patrone M88
(7.9mm Cartridge Model 1888.)
of this case style is not German, instead generally credited to a Colonel Rubin, director
of the Swiss Laboratory at Thun, Switzerland. Feeding in machine guns was a parameter.
Rubin was using compressed black-powder charges behind bullets of 7 to 9mm in diameter in
capacity of the German cartridge came to about 7 percent less than the Lebel.
Nevertheless, ballistics were nearly identical. The Lebel used a 232-grain roundnose
bullet at a published 2,060 fps muzzle velocity; the 7.9mm achieved 2,067 fps with a
had in the 7.9mm M88 cartridge what was without doubt the best military rifle and machine gun cartridge in the world at the time.
This did not mean it was without problems.
unanticipated glitches could only be discovered by using the round in the field and seeing
what didnt work. This occurred with the brass alloy from which the cartridge case
was made. Early 67/33 percent copper/zinc alloy proved too hard, necessitating a softer
72/28 percent mix.
inadequate neck tension allowed the bullet to become loose. Stab crimps were applied to
the neck to remedy this, and eventually neck wall thickness was increased. Then case necks
began cracking at the stab crimp marks. Finally, neck annealing such as used on case necks
today was developed. As machine gun designs progressed, further strength problems with the
case cropped up. All were solved by unseen changes to case wall taper or thickness.
widely debated is the variance of internal barrel dimensions and bullet diameters of early
7.9mm arms and ammunition. The topic often makes use of the terms J-bore, Z-bore,
S-barrel, J-bullet and S-bullet. This writer has reviewed at least eight different
explanations over the years and no two are exactly alike! Lets look at a few facts,
then see if we can figure out what was going on.
first fact is that bore diameter (hole reamed in barrel before rifling) for the 7.9mm
cartridge has always been 7.9mm (.311 inch). Why some call it an 8mm is unknown. The M88
cartridge used an 8.1mm (.3189 inch) diameter bullet (J-bullet). Rifling depth for the M88
barrel was 0.1mm (.0039 inch). Simple addition now reveals that barrel groove diameter
(J-bore) and bullet diameter were identical at 8.1mm.
M88 ammunition with its long, hard jacketed bullet pushed by the new smokeless powder was
fired in these barrels, the rifling quickly wore away and barrels ruptured, split or just
plain blew out in various locations near the breech. Such was not desirable. Failures were
blamed on the bullet being too large in diameter, though erosive, unstable powder was more
likely at fault.
a remedy, rifling groove depth was increased from 0.1mm to 0.15mm. We now have a groove
diameter of 8.2mm (.323 inch). Neither bore nor bullet diameter were changed. These
barrels had a Z stamped on them (Z-bore). Gas
leakage past the bullet stopÂped barrel blow-outs and deeper rifling gave longer barrel
life. Remember, Germany was after better field results from the average soldiers
rifle, not smaller benchÂrest groups.
the 7.9mm S (Spitzgeschoss or pointed bullet)
cartridge was adopted in 1903, its bullet was 8.2mm (.323 inch) in diameter (S-bullet),
very pointed and only 154 grains in weight. Velocity is given as 2,930 fps. Smokeless
powder employed was of a more highly developed type using deterrent coatings to control
burning rate. Gas leakage past the bullet was no longer necessary. Bullets were shorter,
which reduced jacket fouling and rifling wear.
barrels on the strong Model 98 actioned rifles were chambered for the S-cartridge. Weaker
Model 88 rifles having the larger Z-bores were rechambered for the S-cartridge by opening
the chamber neck diameter and freeboring to further relieve pressure. These barrels
received an S stamp (S-barrel).
this isnt confusing enough, military J-bore barrels were sold to private gunsmiths
for many years. Riflemakers also continued to produce barrels having J-bore dimensions
long after they were dropped by the military. Thus where they may show up is anyones
guess. Any early sporter or Model 88 rifle should have its bore slugged before firing.
Pushing a jacketed .323-inch slug down a .318-inch barrel could damage a fine, old rifle.
after adoption of the 7.9mm S-cartridge, its cupro-nickel coated steel jacket was found to
give excessive bore fouling in machine guns. The solution was to replace the cupro-nickel
with Tombak, the German equivalent of gilding metal.
a few years experience with the 7.9mm round, many military-use loadings were developed;
tracer, armor piercing, incendiary, aerial spotting, explosive, ball, grenade launching,
signal, blank, tropical, tool cartridges, multiple bullet and on and on are some of the
varieties. All these and more were either made or contracted
by each of the several nations that
adopted the round as their service cartridge. It is probable that there are more varieties
of the 7.9x57mm round than any other cartridge ever made. At least 40 countries have
loaded the ammunition!
a successful military round meant automatic success in the civilian market as a hunting
cartridge. In Germany, Mauser offered its commercial sporters in the 7.9mm chambering.
Countless small gun builders produced Mauser-actioned hunting rifles for export to Asia,
Africa and South America. Few, however, were seen in the U.S. or Canada.
is safe to say, every producer of sporting ammunition in the world has made 7.9mm at some
time. Varieties are almost as endless as military rounds.
to home, CIL of Canada for many years loaded a 170-grain softpoint at 2,530 fps muzzle
velocity. This yielded 2,415 foot-pounds (ft-lbs) of energy. The slug had a rather blunt
point and was given a streamlined profile in the 1950s. Velocity was also upped to 2,570
America, Federal, Remington and Winchester all offer only one loading today. Its a
170-grain softpoint at 2,360 fps from the
muzzle of a 24-inch barrel. Worry of the rounds being fired in the
old Model 88 Commission Rifle is probably the reason. The 7.9x57mm is far better than
ammunition is a different story. RWS, DWM and Norma turn up the speed significantly.
Bullets weighing 185 to 200 grains are available at published velocities over 2,600 fps.
Bullets of 170 grains can be driven at least 2,700 fps; 150 grainers can reach 3,000 in
some rifles. This equals or exceeds the .308 Winchester.
too can make the 7.9mm shine. There is an adequate variety of high-quality hunting bullets
available, and empty cases are not hard to find. Often the above velocities can be safely
exceeded in individual rifles due to the long throats seen in many 7.9mm chambers. If ever
a round existed that careful handloaders can really make perform, this old cartridge is
it. A little field use will leave experienced riflemen wondering why many of the newer
small cartridges were ever created.