Here's a good article that warns about bore dia.. ht tp://findarticles.com/p/articles/mi_m0BQY/is_11_53/ai_n20512666/pg_2/
The remaining part of the package was the development of the 7.9x57mm (8x57) cartridge. The smokeless flake powder was developed by the Royal Prussian Powder Factory in Spandau while the jacketed bullet was designed by Prussian Major Bode and refined by Major Rubin in Switzerland. The Germans also drew upon Rubin's rimless case design. The final cartridge featured a .318"-diameter, 227-grain, roundnose, jacketed bullet at a velocity of 2,100 fps.
Plenty Made
Approximately, 1.9 million Gew. 88 rifles and carbines were produced by arsenals like Spandau, Amberg, Danzig and Erfurt plus contract makers such as Ludwig Loewe and Steyr. A remarkable fact is the whole Germany army was rearmed with Gew. 88s in a period of only two years. In WWI, they appeared in the hands of the German, Turkish, Austro-Hungarian and Bulgarian armies and over the decades, spread throughout the world, including the American surplus market. A lively trade also developed in converting the Model 88 into functional and sometimes elegant sporters.
In 1903, the Germans officially adopted the "S" or "spitzer" 154-grain bullet with a diameter of .323". Over the next decade, existing stores of Model 88's were updated and modified for the "S" cartridge. Chamber necks and throats were enlarged. Barrels replaced. Sights replaced. Stripper clip lips were riveted or welded to the rear bridge. The back of the front receiver ring was notched to accept the spitzer round. Since the Mannlicher-type clip was now eliminated, the bottom of the Mannlicher magazine box was capped off and a spring-loaded cartridge retainer was installed in the left side of the receiver magazine well. The rifles and carbines adopted for the "S" cartridge were stamped "S" on the front receiver ring.
Caution! Check Before Shooting
But if you are a shooter, be cautious! Even though a Model 88 rifle or carbine may be stamped with an "S", it does not mean it is safe to fire with modern .323" ammunition! The barrel's groove diameter may be .318", .321" or .323". The 1891 Amberg Model 88 pictured in this article arrived from Turkey. It has all the features of an "S" converted rifle, but the barrel has a groove diameter of .318", the original "J" bore dimension. Firing vintage, 227-grain SR RWS "J" bore ammunition in the Amberg generates 3-shot, 100-yard groups of 1 3/4" to 2 1/4" at 2,213 fps. Not bad for an old warhorse!
So slug your barrel, match your bullet to the bore, and keep your velocity down to 2,200 fps or less. Cast bullets are a natural for the Gew. 88. Just remember surplus Gew. 88's are now 119-years old and were Germany's first smokeless powder arms. Treat them gently.
My hat's off to the Spandau Commission. In approximately one year, it produced not only an attractive, accurate and thoroughly modern military rifle but the smokeless cartridge Germany staked its fate on for the next 57 years. The Gew. 88 and the 7.9x57 are a remarkable pair.
FURTHER READING GERMAN MILITARY RIFLES AND MACHINE PISTOLS 187t-1945
