5mm Remington Rimfire Magnum

The 5mm Remington Rimfire Magnum or 5mm RFM 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 the round never became very popular, and the rifles were discontinued in 1974. 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, leaving owners with no source of ammunition.
In 2008, the cartridge was reintroduced by Mexico's Aguila Ammunition in collaboration with Centurion Ordnance.
Design.
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 at 33,000 PSI. It uses a 5 mm (.204 caliber) bullet that measures , the same as the more recent .204 Ruger center fire cartridge.
From 1982 until 2008, no ammunition manufacturers manufactured rounds for this cartridge. Some firearms manufacturers even created conversion kits to allow the existing 5 mm guns to shoot other more-common cartridges.
At the 2008 SHOT Show, Aguila Ammunition announced it would reintroduce the cartridge and begin commercial production of 5mm 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 5mm 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 grain projectile and have a muzzle velocity of 2,300 fps.
Performance.
The 5 mm RRM offers higher velocity than the .22 WMR and more energy than both the .22 WMR and the later .17 HMR. It offers improved performance on small-game and for varmint hunting, along with excellent accuracy. The Aguila/Centurion 5mm Remington Magnum ammunition comes in two types: the original "white box" with a 30 gr dimpled jacketed soft point at 2,300 fps, as well as a varmint "yellow box" round with a 30 gr jacketed hollow point at 2,400 fps. Chronograph testing has shown that these rounds can actually run about 100 fps faster than claimed by Aguila.
5mm Craig centerfire conversion.
When Remington discontinued production of 5mm RFM ammunition, owners of Remington 591 and 592 rifles were left with excellent rifles but no ammunition for them. Mike Craig, in 1994, in Seattle, began work on a centerfire conversion of the 5mm RFM, the 5mm Craig. 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 5mm Craig to Eagle View Arms of Shelton, Washington.
Firearms chambered for 5mm RRM.
Original 591M and 592M rifles are still occasionally available on gun auction websites and at local gun shops and shows, prices running in the $500.00, plus or minus, range (2013).
For a brief time, Thompson Center Arms offered firearms in 5mm Mag.
At the 2008 SHOT show, Taurus International introduced the first handgun chambered for the 5mm Remington Magnum Rimfire. Concurrent with the announcement from Taurus, Aguila Ammunition announced they would begin producing 5mm RFM ammunition in 2008.
As of May 2011, Taurus has not yet imported nor produced their Tracker in 5mm RFM. They had stated that it will be manufactured and imported pending production demand in the second half of 2010.