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17 Hornady Magnum Rimfire (HMR)

Perhaps no other new cartridge has generated so many printed words in such a short time by so many writers as the 17 HMR. Introduced in 2002, the 17 HMR was the first new rimfire cartridge since the short-lived 5mm Remington. However, the 17 HMR certainly will not suffer a similar fate! The number of rifles and handguns available in 17 HMR caliber is very large. This is natural because the 17 HMR case is simply a 22 WMR case necked down to hold a 17-caliber bullet. Therefore, a firearm designed around the 22 WMR can be made into a 17 HMR simply by changing the barrel. Even the magazines that hold 22 WMR cartridges will feed 17 HMR cartridges. Because so many firearms in 22 WMR caliber were already in production, there are now many that are also produced in 17 HMR.

Nominal bullet diameter for the 17 HMR is 0.172”. The original load consisted of a 17-grain Hornady V-Max polymer tipped bullet that was loaded to a velocity of 2,550 ft/sec giving an energy of 245 ft lbs. The well-shaped bullet has a ballistic coefficient of 0.125 so it holds velocity well which results in a rather flat trajectory that makes hits on small pests possible out to 150 yards or more. Although many larger varmints have been taken with the 17 HMR, the cartridge is at its best when used on species like ground squirrels, crows, pigeons, and prairie dogs. Early reports by some writers described the use of the 17 HMR on species as large as coyotes, but many reports have also described failures of the tiny bullets on larger pests like groundhogs, foxes, and coyotes. One of the most interesting discussions on the 17 HMR is that by C. Rodney James which was published in Gun Digest 2005. In an article published in the February 2005 issue of Predator Xtreme, Ralph Lermayer has related some of his experiences on the failure of the 17 HMR as a cartridge for use on larger varmints. Recently, loads employing 20-grain hollow-point bullets having a muzzle velocity of 2,375 ft/sec have been introduced to reduce the explosive character. This ammunition may help reduce bullet fragmentation, but the tiny 17 HMR was never really intended for use on larger species of varmints. Nonetheless, the 17 HMR is a great little cartridge that gives outstanding accuracy, and we will have a lot to say about it in other chapters of this book. Incidentally, it was the development of suitable propellants that made the ballistics given by the 17 HMR possible. Had such propellants been available at the time the 5mm Remington was introduced, the 17 HMR might never have been developed.