.17 Hornady Magnum Rimfire, commonly known as the .17 HMR, is a rimfire rifle cartridge developed by

Hornady Hornady Manufacturing Company is an American manufacturer of ammunition cartridges, components and handloading equipments, based in Grand Island, Nebraska. History The company is currently run by Joyce Hornady's son, Steve Hornady, who took ov ...

in 2002. It was developed by necking down a .22 Magnum case to take a .17

caliber In guns, particularly firearms, caliber (or calibre; sometimes abbreviated as "cal") is the specified nominal internal diameter of the gun barrel bore – regardless of how or where the bore is measured and whether the finished bore ma ...

(4.5 mm) projectile. Commonly loaded with a 17

grain A grain is a small, hard, dry fruit ( caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legu ...

(1.1 g) projectile, it can deliver muzzle velocities in excess of 775 m/s (2,650 ft/s).

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 A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete tr ...

. These wildcatters were seeking to match the ballistics of the obsolete

5mm Remington Rimfire Magnum The 5mm Remington Rimfire Magnum or 5mm RFM
by Chuck Hawks is a bottlenecked 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 .204 Ruger), the commercially available .17 caliber became their bullet of choice. The .22 Winchester Magnum Rimfire was the logical parent case, rather than the 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 .22 Long Rifle. The .17 caliber wildcats not only met but far exceeded the 5mm RMR's velocities and flat trajectory. The accuracy of these cartridges was also quite good. However, the downrange energy of the 5mm RMR is superior to both .22 WMR and .17 HMR, so there is still potential in the 5 mm rimfire for wildcatters. Hornady, in conjunction with

Marlin Firearms Marlin Firearms Co. is an American manufacturer of semi-automatic, lever-action, and bolt-action rifles. In the past, the company, now based in Madison, North Carolina, and formerly based in North Haven, Connecticut, made shotguns, derringer ...

and Sturm, Ruger & Co. (manufacturers in the rimfire rifle market), 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

rifle A rifle is a long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves (rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with b ...

s and ammunition began appearing on the market. While the ammunition was relatively expensive due to the high-performance .17 caliber bullets used, it was still cheaper than most centerfire ammunition. By 2004, CCI, Federal Cartridge and Remington had each introduced .17 HMR ammunition offerings.

Availability

Cartridges for .17 HMR come with bullets that weigh , , and , and come in designs such as plastic-tipped bullets, hollow points, soft points, and FMJs. The

terminal ballistics Terminal ballistics (also known as wound ballistics) is a sub-field of ballistics concerned with the behavior and effects of a projectile when it hits and transfers its energy to a target. Bullet design (as well as the velocity of impact) larg ...

of the lightweight expanding bullets limit the .17 HMR to small 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. 17HMR rounds2

A growing number of companies offer .17 HMR ammunition. CCI Ammunition loads all of the .17 HMR ammunition for the CCI, Federal Cartridge,

, and Remington brands. However, the ammunition is loaded with different bullets to different specifications. Ammunition is also available from

Winchester Winchester is a cathedral city in Hampshire, England. The city lies at the heart of the wider City of Winchester, a local government district, at the western end of the South Downs National Park, on the River Itchen. It is south-west of Lon ...

, PMC and Sellier & Bellot. Examples of

bolt-action Bolt-action is a type of manual firearm action that is operated by ''directly'' manipulating the bolt via a bolt handle, which is most commonly placed on the right-hand side of the weapon (as most users are right-handed). Most bolt-actio ...

lever-action The toggle-link action used in the iconic Winchester Model 1873 rifle, one of the most famous lever-action firearms Lever-action is a type of action for repeating firearms that uses a manually operated cocking handle located around the trigger g ...

rifles that are chambered for (or have variants chambered for) .17 HMR include Armscor M1700, Browning T-Bolt, CZ 452, Ruger Model 96, Savage 93, Steyr Zephyr II, Marlin 917 and Weihrauch 60J. Citing safety concerns about the round's use in

semi-automatic firearm A semi-automatic firearm, also called a self-loading or autoloading firearm (fully automatic and selective fire firearms are also variations on self-loading firearms), is a repeating firearm whose action mechanism ''automatically'' loads a follow ...

s, Remington issued a product safety warning and recall notice.

.17 Hornady Mach 2

Following the success of the .17 HMR, the .17 Hornady Mach 2 was introduced in early 2004. The .17 HM2 is based on the .22 LR (slightly shorter in case length) case necked down to .17 caliber using the same bullet as the HMR but at a velocity of approximately in the polymer tip loading.

References

External links

Varmint Al's
Field Testing the .17 HMR {{DEFAULTSORT:17 HMR Pistol and rifle cartridges Rimfire cartridges Weapons and ammunition introduced in 2002

Development

Availability

.17 Hornady Mach 2

See also

References

External links