The 7.5x55mm Swiss (7.5x55 Schmidt Rubin)
By Chuck Hawks
The 7.5x55 cartridge has been in Swiss Army service since 1889. It was used in a succession of models of the Schmidt-Rubin straight pull bolt action rifle, and then was adapted to the Model 57 assault rifle. The latter went into widespread service sometime around 1980. The 7.5mm Swiss has got to be one of the oldest cartridges still in service with a modern army in the entire world.
Analogous to the "JS" version of the 8x57, the 1911 version of the 7.5x55 cartridge uses a .307" (7.62mm), 174 grain FMJ boat tail spitzer bullet at a muzzle velocity (MV) of 2640 fps. This higher velocity and higher pressure (46,000 psi) load with its larger diameter bullet cannot be used in the original Model 1889 rifle, but is safe in the Model 1896/11 and all subsequent versions of the Schmidt Rubin infantry rifle.
Schmidt-Rubin rifles are not strong enough for "hot" reloads. Use ONLY standard pressure loads.
The 7.5mm Swiss cartridge is based on a rimless (.495" rim diameter), bottle neck case with a sharp 30.5 degree shoulder angle. This case is 55mm (2.140") long and, despite its "7.5mm" nomenclature, takes 7.62mm (.308") bullets.
Commercial ammunition for the 7.5x55 is loaded in Europe but not, as far as I know, in North America. Norma of Sweden offers 7.5x55 brass and loaded ammunition to shooters in the US. Norma 7.5x55 factory loads give a 180 grain soft point bullet a MV of 2651 fps and muzzle energy of 2810 ft. lbs. The figures at 200 yards are 2223 fps and 1976 ft. lbs.
Since the 7.5x55 can be reloaded with standard .308" bullets, there is a vast selection of bullets available to the handloader, from 100 grains to 220 grains. The usual 150, 165 and 180 grain weights will do pretty much whatever can be done with the 7.5x55 as a big game hunting cartridge.
According to data published in the Hornady Handbook, Third Edition their 150 grain Spire Point bullet can be driven to a MV of 2400 fps by 38.4 grains of H4895 powder, and 2800 fps by 46.7 grains of H4895. The trajectory of that load looks like this: +2" at 100 yards, 0 at 200 yards, -8.8" at 300 yards.
Hornady's 165 grain Spire Point bullet can be driven to a MV of 2200 fps by 34.5 grains of H4895 powder, and a MV of 2700 fps by 45.5 grains of H4895. The trajectory of that load looks like this: +2.1" at 100 yards, 0 at 200 yards, and -9.2" at 300 yards.
The 180 grain Spire Point bullet can be driven to a MV of 2100 fps by 38.1 grains of IMR 4350 powder, and 2500 fps by 47.5 grains of IMR 4350. At 2500 fps the ME is 2499 ft. lbs. The Hornady trajectory figures for this bullet look like this: +2.6" at 100 yards, 0 at 200 yards, and -10.5" at 300 yards.
Note: A full length article about the 7.5x55 can be found on the Rifle Cartridge Page.
Copyright 2005 by Chuck Hawks. All rights reserved.