The 5 mm Remington Rimfire Magnum or 5 mm RFM[2] is a bottlenecked rimfire cartridge introduced by Remington Arms Company in 1969. Remington chambered it in a pair of bolt-action rifles, the Model 591 and Model 592, but this ammunition never became very popular, and the rifles were discontinued in 1974.[3] About 52,000 rifles and 30,000 barrels for the T/C Contender pistol were sold during its brief production run. Remington discontinued the cartridge itself in 1982,[3] leaving owners with no source of ammunition.[4][5]
In 2008, the cartridge was reintroduced by Aguila Ammunition in collaboration with Centurion Ordnance.[6][7][8][9]
Remington designed a completely new, bottlenecked case that was somewhat similar to the older .22 Winchester Magnum, but stronger to handle the higher pressure of the 5 mm (0.20 in) at 37,000 psi (260 MPa).[2][10]
Between 1982 and 2008, no ammunition was being manufactured. Some firearms manufacturers even created conversion kits to allow the existing 5 mm guns to shoot other more-common cartridges.[5]
At the 2008 SHOT Show, Aguila Ammunition announced it would reintroduce the cartridge and begin commercial production of 5 mm RFM ammunition. Until 2019, the cartridges were sold in the United States of America under the Centurion brand. In 2019, Aguila Ammunition announced the company now offered two 5 mm RFM loads: one with a semi-jacketed hollow point bullet and a second with a full jacketed hollow point bullet. Both loads use a 30 gr (1.9 g) projectile and have a muzzle velocity of 2,300 ft/s (700 m/s).[11]
The 5 mm RRM offers higher velocity and more energy than the .22 WMR and the later .17 HMR.[6] It offers improved performance on small game and for varmint hunting, along with excellent accuracy.[1]
When Remington discontinued production of 5 mm RFM ammunition, owners of Remington 591 and 592 rifles were left with excellent rifles but no ammunition for them. In 1994, Mike Craig of Seattle, Washington began working on a centerfire conversion of the 5 mm RFM, called the 5 mm Craig.[12][13] His company, Certech, also performed conversions of 5 mm rifles from rimfire to centerfire by altering the bolts and installing new firing pins, restoring them to use. Craig has since sold all the rights to the 5 mm Craig to Eagle View Arms of Shelton, Washington.[13]
For a brief time, Thompson Center Arms offered firearms in 5 mm Mag.[5]
At the 2008 SHOT show, Taurus International introduced the first handgun chambered for the 5 mm Remington Magnum Rimfire.[14]