While the ammunition was relatively expensive due to the high-performance. In 2002, the first rifles and ammunition began appearing on the market. 22 WMR firearms to chamber the new cartridge. 22 WMR case as the starting point, a simple barrel change was sufficient for most. (manufacturers in the rimfire rifle market), followed much the same path. Hornady, in conjunction with Marlin Firearms and Sturm, Ruger & Co. 17 HMR, so there is still potential in the 5mm rimfire for wildcatters. However, the downrange energy of the 5mm RMR is superior to both. The accuracy of these cartridges was also quite good. 17 caliber wildcats not only met, but far exceeded the 5mm RMR's velocities and flat trajectory. 22 Winchester Magnum Rimfire was the logical parent case, rather than 5mm RMR (with its unique case head size, which requires a significantly different bolt and magazine), because it was commonly available, and it is a far larger and stronger case than the next largest, the. 17 caliber became their bullet of choice. With 5 mm diameter barrels and bullets being virtually unavailable at the time (the 5mm RMR was the last commercial 5 mm round until the 2004 release of the centerfire. These wildcatters were seeking to match the ballistics of the obsolete 5mm Remington Rimfire Magnum, which was made from 1970 to 1974, and was to that point the fastest rimfire cartridge ever produced. 17 HMR round is similar to rounds developed by dedicated rimfire wildcatters who worked to create a rimfire cartridge with an exceptionally flat trajectory. Commonly loaded with a 17 grain (1.1 g) projectile, it can deliver muzzle velocities in excess of 775 m/s (2,650 ft/s). 17 HMR, is a rimfire rifle cartridge developed by the ammunition company Hornady in 2002. 17 Hornady Magnum Rimfire, commonly known as the. 17 HMR round with a light green plastic tip.ĬCI, Federal, Hornady, PMC, Remington, Winchester