The .17 Hornady Magnum Rimfire
By Chuck Hawks
Introduced in 2002, the .17 Hornady Magnum Rimfire (.17 HMR) is the first new rimfire cartridge since the ill-fated 5mm Remington of 1970. The last successful rimfire cartridge was the .22 Winchester Magnum Rimfire (.22 WMR) of 1959.
Hornady, like Remington with their short-lived 5mm, ventured into uncharted rimfire waters with a caliber other than .22. Although there have historically been a wide variety of moderately successful rimfire cartridges in calibers larger than .22, in modern times .22 has been the rimfire caliber, and there has never been a successful caliber smaller than .22. The overwhelming shooter acceptance of the .17 HMR has changed that.
The .17 HMR has more going for it in terms of name recognition than the 5mm Remington had, as many shooters have probably at least heard about some of the various .17 caliber centerfire cartridges. .17 is an unusual caliber, but not as weird as 5mm, for which there was almost no precedent. Those who are aware of the .17 caliber centerfire cartridges, such as the .17 Mach IV and .17 Remington, probably associate them with ultra-high velocity, which can only rebound to the .17 HMR's advantage, as it is the fastest rimfire in history.
In developing the .17 HMR, Hornady was aided by rifle makers Marlin and Ruger. Together they were seeking the highest velocity possible in a rimfire cartridge consistent with reliability, accuracy, and reasonable manufacturing economy. The .17 HMR was designed to outperform the .22 WMR in velocity and trajectory, and be less susceptible to wind drift. It was also to have a similar maximum range, no greater noise level, be less susceptible to ricochet, and operate at the same pressure. All this in a cartridge designed to meet an intrinsic accuracy standard of 1 minute of angle (MOA) or better.
The new cartridge also had to be adaptable to existing rimfire rifle designs. They settled on a .22 WMR case, the largest and strongest rimfire case available, necked down to accept a .172 inch diameter bullet. The maximum overall length of the cartridge is 1.35 inches, the same as that specified for the .22 WMR, insuring that it will fit in the magazines and work through the actions of rifles designed for the .22 WMR cartridge. The result is a bottleneck rimfire case about the length of the .22 WMR case with a small but definite 25-degree shoulder.
In order to achieve the highest possible velocity, a bullet weight of just 17 grains was chosen, and Hornady designed a new V-Max bullet specifically for the .17 HMR. Hodgdon Lil' Gun powder was selected for use in the cartridge.
In form the 17 grain bullet appears to be a boat-tail spire point. In order to raise the ballistic coefficient (BC) of this very stubby bullet a large polymer tip was incorporated into its design. Proportionally, the 17 grain V-Max bullet has the biggest polymer tip I have ever seen. It accounts for about 28.5% of the overall length of the bullet. I calculated the sectional density (SD) of this bullet at .084, the lowest of any bullet on the market. Over penetration is unlikely to be a problem with the .17 HMR!
The Hornady varmint load for the .17 HMR advertises the 17 grain V-Max bullet at a MV of 2550 fps and ME of 245 ft. lbs. The figures for 100 yards are 1901 fps and 136 ft. lbs. Hornady trajectory figures show that when zeroed at 100 yards, this bullet hits only 0.1" high at 50 yards, and 2.6" low at 150 yards.
A better way to zero a .17 HMR rifle is to put the 17 grain bullet 1.5" high at 100 yards, for a zero range of 145 yards. It would then hit about 0.9" high at 50 yards, 0.3" low at 150 yards, and 5.5" low at 200 yards. The maximum point blank range (+/- 1.5") of the cartridge would be about 165 yards, at which range the bullet retains about 90 ft. lbs.of energy, enough to remain effective on the smaller varmints.
These figures are based on a bullet with a BC of .123, which I derived from the Hornady velocity and trajectory figures. Hornady and Speer have not released the BC's of their .17 HMR bullets, but I feel confident that my estimate is very close for the .17 grain V-Max bullet.
In 2004 Hornady expanded their line of .17 HMR cartridges by offering a second load using a 20 grain XTP bullet (SD .097) at a MV of 2375 fps and ME of 250 ft. lbs. Zeroed at 100 yards, this bullet will hit 3.2" low at 150 yards, according to Hornady figures. This bullet equals the SD of the 34 grain .22 WMR bullet. It is a controlled expansion bullet designed for small game hunting, rather than a frangible varmint bullet like the 17 grain V-Max bullet.
Sight that load to take advantage of its MPBR (+/- 1.5") of 154 yards and the point of zero would be 134 yards for a bullet with a BC of .123. (Which I believe, coincidentally, to also be the BC of the 20 grain Hornady XTP bullet, based on the Hornady velocity and trajectory tables.) The trajectory would then look like this: +1" at 50 yards, +1.3" at 100 yards, -1.2" at 150 yards, and -7.6" at 200 yards.
The .17 HMR is intended for hunting animals such as squirrels, rabbits, prairie dogs, gophers, marmots, and other small creatures. This is the same class of game appropriately hunted with a rifle chambered for the .22 Magnum cartridge. However, the superior velocity and flat trajectory of the .17 HMR extends the humane range. Early reports from the field suggest that consistent one shot kills on ground hogs are possible at 150 yards if the shooter has the skill to get the bullet into a vital spot.
With its intrinsic MOA accuracy, the .17 HMR cartridge is accurate enough to score clean kills on small game at 150 yards. The small game hunter with a .17 HMR rifle is pretty much out of excuses for his misses, at least on a calm day. But beware of the wind! A 10 MPH cross wind will blow the 17 grain V-Max bullet 8" laterally at 150 yards, or the 20 grain XTP bullet 8.8" off course at the same range.
Marlin and Ruger offered the initial rifles chambered for the .17 HMR. Both companies adapted existing bolt action repeaters to the new cartridge. In Marlin's case this is their medium-low priced Model 917V (blue) and medium priced 917VS (stainless steel) varmint rifles, and in Ruger's case their medium-high priced Model 77/17 (sporter) and 77/17VBZ (varmint) rifles.
Subsequently, CZ brought out .17 caliber versions of their bolt action rimfire rifle. Savage introduced their stainless steel/laminated stock Model 93R17-BVSS varmint rifle and three variations of their Model 93R17 small game hunting rifle. Anschutz is chambering their upscale Model 1717D and 1517 bolt action rifles for the .17 HMR.
New England Firearms (owned by Marlin) has an inexpensive, break-action, single shot rifle for the .17 Hornady. Savage/Stevens has their more expensive Model 30R17 falling block single, and Winchester offers their deluxe Model 1885 Low Wall in .17 HMR. In addition, Thompson/Center is offering the .17 HMR in their single shot rifle.
The .17 HMR is also available in lever action repeating rifles from Henry and Winchester, and Remington has adapted their Model 597 autoloader to the cartridge. Rossi has added it to their Youth Rifle, and Taurus offers the .17 HMR in their pump-action rifle. These, along with other newly annnounced rifles, completely cover the rimfire rifle price range from low to high. It is fair to say that practically everyone who can build a .17 HRM rifle is now doing so.
Handgun manufacturers quickly jumped on the .17 HMR bandwagon. Thompson/Center and Savage single shot pistols are easily adaptable to rifle cartridges and were the first to be announced. Ruger, Smith & Wesson, and Taurus adapted existing revolvers to the .17 HMR, much as they had the earlier .22 WMR.
Even more promising were the 2003-2004 announcements by CCI, Federal and Remington that they were commencing distribution of .17 HMR ammunition under their brand names. CCI will continue to manufacture the .17 HMR ammo for all four brands, but the load specifications vary. The 2003 Remington catalog shows that their initial .17 HMR offering is in their Premier line, uses the 17 grain V-Max boat tail bullet, and has identical ballistics to the Hornady load. The Federal and Speer loads use a 17 grain Speer TNT (hollow point) spitzer bullet, with the Federal load at 2550 fps and the CCI load at 2525 fps. Ammunition of all brands, initially in short supply, is now widely available and is selling for about $8.95/50 round box at discount stores in my area.
This acceptance of the .17 HMR on the part of gun and ammunition manufacturers, as well as consumers, is both surprising and pleasing. It seems that the .17 HMR has become a huge commercial success, expanding the choice and capabilities of rimfire cartridges in the 21st Century.
Copyright 2002, 2012 by Chuck Hawks. All rights reserved.