The 5.2×68mm Rubin, also known as the 5.2×68mm Mondragón, was an early smokeless powder cartridge used in the Mondragón M1894 rifle.[1]
Design Details[]
Designed by Swiss Army Colonel Eduard Rubin[1] in collaboration with Manuel Mondragón, the 5.2×68mm cartridge is distinguished by its case design and small-bore projectile.
The casing came in two variations, one with an extractor groove and one without.
The cartridge has an internal brass washer ring within the casing, increasing the case volume (therefore, moderating the gas pressure) as the bullet left the case. To prevent the washer from falling into the bottom, the casing has a crimp to secure it in place.
The .208 caliber projectile weighs 90 grains (5.83 grams) and measures 1.2 inches (30.48mm) in length, and is fired at a muzzle velocity of 2,900 feet per second (883.92 meters per second). This was at a time where black powder-driven bullets had maxed out at 1,400 to 1,500 feet per second.
Rounds are fed into the M1894's internal magazine via 6-round en-bloc clips.
Drawbacks[]
The cartridge occasionally had problems with the internal washer ring breaking up and lodging in the bore of the weapon.
In addition, the casing could only be used once, due to its design.