.17 HMR

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(Redirected from .17 Hornady Magnum Rimfire)

.17 Hornady Magnum Rimfire, commonly known as the .17 HMR, is a rimfire rifle cartridge descended from the .22 Magnum. It was developed by necking down the .22 Magnum case to take a .17 caliber (4.5 mm) bullet. Commonly loaded with a 17 grain (1.1 g) bullet, it can deliver muzzle velocities in excess of 2550 ft/s (750 m/s). It is widely considered to be the most accurate of the rimfire cartridges.

1 Development
2 Firearms
3 Availability
4 See also
5 External links

[edit] Development

The .17 HMR round is similar to rounds developed by dedicated rimfire wildcatters who worked to create a rimfire cartridge with an exceptionally flat trajectory. These wildcatters were seeking to match the ballistics of the obsolete 5 mm (.20 caliber) Remington Magnum Rimfire, which was made from 1970 to 1974, and was to that point the fastest rimfire cartridge ever produced. With 5mm (.20 caliber) diameter barrels and bullets being virtually unavailable at the time (the 5mm RMR was the last commercial 5mm round until the 2004 release of the centerfire .204 Ruger), the commercially available .17 caliber became their bullet of choice. The .22 WMR was the logical parent case, as was also the basis for the 5mm RMR, as it was commonly available and had a far larger and stronger case than the next larger .22 Long Rifle. The .17 caliber wildcats not only met, but far exceeded the 5 mm RRMR's velocities and flat trajectory. The accuracy of these cartriges was also quite good. The downrange energy of the 5mm RMR is still superior to both .22 WMR and .17 HMR, however, so there is still potential in the 5mm rimfire for wildcatters.

Hornady, in conjunction with Marlin Firearms and Sturm, Ruger, followed much the same path. With the .22 WMR case as the starting point, a simple barrel change was sufficient for most .22 WMR firearms to chamber the new cartridge. In 2002 the first rifles and ammunition began appearing on the market, and the .17 HMR was an instant hit. While the ammunition was relatively expensive due to the high-performance .17 caliber bullets used, it was still cheaper than most centerfire ammunition. The availability of moderately priced and accurate firearms from Marlin and Ruger (leaders in the rimfire rifle market) plus the backing of a major ammunition maker allowed the .17 HMR to quickly gain momentum. Other makers of firearms and ammunition soon introduced .17 HMR offerings.

[edit] Firearms

The original .17 HMR rifles were bolt action and based on .22 WMR actions. Single-shot and lever action rifles are now available, as well as various single action and double action revolvers, and even Semiautomatic rifles. Many rifles can be procured from local gun shops for prices considerably less-around 200$- than other rifles which makes them an ideal choice for backyard plinkers.

[edit] Availability

Image:17HMR rounds2.jpg

Due to the specialized bullets the .17 HMR uses, there is only a narrow range of ammunition available for it. The bullets generally weigh from 17 to 20 grains, and have expanding designs such has hollow points or soft points. The terminal ballistics of the lightweight expanding bullets limit the .17 HMR to the smallest of game animals and varmints. .17 HMR ammunition is less common and more expensive than the .22 caliber rimfire rounds, but this is changing as the popularity of .17 HMR rifles gathers momentum. In the UK, the .17 HMR round is favoured by many Police firearms licensing departments over the .22 LR, as due to its high speed it is thought less prone to ricochet.

.17 HMR rifles and ammo have continued to sell briskly long after gun retailers expected sales to have tapered off. Following the success of the .17 HMR, the .17 Hornady Mach 2, or .17 HM2, was introduced in early 2004. The .17 HM2 is based on the .22 LR case, but necked down to .17 caliber.