The 5mm Remington Rimfire Magnum cartridge is a bottlenecked rimfire cartridge introduced to the market by Remington Arms Company in 1969. Remington chambered it in a pair of bolt-action rifles, the Model 591 and Model 592. The ammunition was never widely used and the rifles were discontinued in 1974. About 52,000 rifles and 30,000 barrels of the T/C Contender pistol were sold during its brief production run. Remington discontinued the cartridge itself in 1982, leaving owners with no source of ammunition.
In 2008, the cartridge was reintroduced by Mexico's Aguila Ammunition in collaboration with Centurion Ordnance.
Cartridge Dimensions
Visit Wikipedia for more information and sources.