Copyright International Ammunition Association, 2007. All rights
reserved.
Cartridge of the Month
July 2007
5.2 x 68 mm Mondragon (with piston)
Specimen and photos courtesy of Paul
Smith
This was one of the earliest small calibers rounds. It was designed by the Swiss Colonel Rubin in 1894 for a semi-automatic rifle to be built by the Swiss, the rifle being a design by Mexican Manuel Mondragon. This was the first semi-automatic rifle to reach production (although by then chambered for conventional 7 x 57 mm Mauser cartridges. It was made in limited numbers (about 4,000 total), and after Mexican default on the contract the remaining rifles ended up being sold to Germany where they were used as aircraft weapons during World War I.
The projectile has a cupro-nickel clad steel (CNCS) jacket and brass ring at the base.
According to the Rubin’s patent, the piston ring around the base of the bullet allows for more energy to be used to drive the projectile than a conventional design. The piston ring is stopped at the shoulder while the projectile continues down the barrel. The projectile is 31 mm in length and had a muzzle velocity of about 800 m/s (2,600 f/s).
Visible on the outside of the case is a smooth cannelure. The piston ring sits on this indentation. Presumably the case is necked after the projectile assembly has been seated.
Note: because of the chemical composition of early smokeless powder, many of
these rounds have started to deteriorate inside.
The powder used in this
section is of a similar time period and shape, but not original to this round.
The headstamp is ‘POLTE MAGDEBURG’
Reference: Military rifle & Machine Gun Cartridges by Jean Huon. p. 32