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AMMUNITION .22WMR VERSUS .17HMR Introduction I have been considering this article for some time and as a result of being between two rifle projects at the moment I decided to do a write up on the benefits of the .22 Winchester Magnum Rimfire (WMR) over the .17 Hornady Magnum Rimfire (HMR). "NEVER" I hear people saying, well read on to discover why the 51 year old WMR cartridge is a more effective cartridge. Currently, sales of .22WMR are down and this is because it now has an overly publicised competitor in the market place. Whether the WMR will survive it is hard to say as the ammunition market is a fettle thing, with cartridges coming and going but hopefully like the 45/70, 6.5 Swedish and the .22 Hornet, the .22WMR will stand the test of time.

Brief History I have no intention of writing pages and pages of history on the two cartridges; you can find that elsewhere in various publications. The .22WMR was introduced by Winchester in 1959 and is generally loaded with 40gr jacket bullet with a velocity of 1900fps and carries 324lbs of energy, making it the most potent rimfire cartridge available. Whilst the cartridge is almost double the length of a .22LR it did not originate from that heritage but in fact heralded from the now obsolete .22 Winchester Rimfire (WRF). The WMR's case is thicker than the .22LR to accommodate the higher pressures and the bullet diameter is .224, where a .22LR is .222. Although used by a small dedicated group of wildcatters this is a pure hunting cartridge with a range of 125yrds and is effective against game as large as fox's or coyotes. The .17HMR was introduced in 2002 amid a huge press release. The cartridge was almost an overnight success with manufacturers initially unable to produce enough ammunition to satisfy demand. The cartridge was developed by Hornady and descended from the .22WMR. It was developed by necking down the WMR to take a 17grn bullet which could deliver velocities of around 2550fps.

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AMMUNITION .22WMR VERSUS .17HMR Technical Specifications .17 HMR .22WMR Bullet Diameter .172 in (4.38mm) .224 in (5.7mm) Neck Diameter .195 in (4.98mm) .240 in (6.1mm) Shoulder Diameter .240 in (6.07mm) N/A Base Diameter .241 in (6.11mm) .241 in (6.1mm) Rim Diameter .291 in (7.4mm) .291 in (7.4mm) Case Length 1.052 in (26.7mm) 1.052 in (26.7mm) Overall Length 1.349 in (34.2mm) 1.35 in (34mm) Primer Type Rimfire Rimfire Source: Cartridges of the World 11th Edition Sound Attenuation Ballistic Performance .17HMR .22WMR Bullet Weight Velocity (fps) Energy Bullet Weight Velocity Energy 17grs 2550 245lbs 30grs 2200 322lbs 20grs 2350 250lbs 40grs 1910 324lbs N/A 50grs 1650 300lbs th Source: Cartridges of the World 11 Edition Pros & Cons .17 HMR Velocity (Pro): The velocity of the HMR is clearly superior to the WMR and this gives it the advantage of shorter time to impact. Trajectory (Pro): With a higher velocity the bullets trajectory is flatter and thus is easier to shoot as there is less need to "aim off". Personally I think this is one of the cartridges key points to its popularity. Kinetic Energy (Con): The very light bullet cannot carry sufficient kinetic energy for an "efficient kill" on larger animals such as fox's or coyotes. It also destroys the meat on smaller animals such as rabbits if you intend to put the meat on the table. Accuracy (Pro): I personally feel the HMR has a clear advantage when it comes to pin point accuracy over the short stubby bullet of the WMR. Environmental (Con): The bullets lack of weight is a disadvantage in strong winds, rain or shooting in vegetation were grass may deflect the bullet. Barrel Deposits (Con): I find the HMR very dirty when it comes to barrel deposits and these deposits do affect accuracy if the barrel is not regularly cleaned. Bullet Types (Con): Three types that I am aware of, hollow point, soft point and ballistic tip. Bullet Weights (Con): Limited to 17 & 20grns. Attenuation (Con): This was a marginal 134.5db(a) difference, a different moderator or rifle with a longer barrel would have equalised this. Other (Con): Currently this cartridge cannot be used in semiautomatic firearms although I am sure this is only a temporary problem. 2 Thames Valley Guns

AMMUNITION .22WMR VERSUS .17HMR .22 WMR Velocity (Con):

The velocity of the WMR is clearly inferior to the HMR; however this is only a marginal 100fps with the ballistic tipped 30grn bullet. Trajectory (Con): Due to the laws of gravity the heavier bullet has a more curved trajectory and thus requires more skill to successfully engage targets at longer ranges. Kinetic Energy (Pro): The heavier bullet is a far more efficient killing round as it possesses more kinetic energy for larger larger animals such as fox's or coyotes. However it will also destroy meat on smaller animals such as rabbits. Accuracy (Con): With the WMR's short stubby bullet, I have been unable to better the HMR when it comes to pin point accuracy. Environmental (Pro): The bullets weight has a clear advantage in strong winds, rain or shooting in vegetation were grass may deflect the bullet. Barrel Deposits (Pro): Normal with no excessive deposits and no special cleaning required Bullet Types (Pro): Six types that I am aware of, hollow point, soft point, and a combination of hollow and soft point, ballistic tip, FMJ and shotshell. Bullet Weights (Pro): Far better with the WMR with 30, 40 & 50grns. Attenuation (Pro): This was a marginal 133.5db(a) difference, a different moderator or rifle would have equalised this. Other (Pro): As this cartridge has been around for a long time it has been successfully adopted for many semiautomatic designs. The pictures on the right show the accuracy of the two cartridges with the .22 WMR on the left and the .17HMR on the right both shot at 100yrds. There were no special conditions other than they were shot of the bench on a windless day. The WMR was shot using a Mauser 201 and the HMR using a CZ 452 Varmint. Both cartridges were manufactured by Federal. The WMR group is 1½" and the HMR ½". Summary As you have probably guessed by now this is not a scientific report, it is a user's report based on knowledge and experience. Besides the heavy media hype that the .17HMR has enjoyed; the real reason for the HMR's popularity is that it is "User friendly" with its high velocity, flat trajectory and superior accuracy. However the above "pro & cons" paragraph clearly indicates the venerable .22WMR as the superior cartridge. The reason is quite simply the .22WMR is more effective at putting the target down and keeping it down. In warfare the same criteria applies; the .308 Winchester cartridge, as is far more effective than the more modern .223 Remington at removing the enemy soldier from the battlefield.

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AMMUNITION .22WMR VERSUS .17HMR Unfortunately on numerous occasions I have witnessed shooters deliver multiple HMR hits to foxes, only to see the animal escaped into the undergrowth to face a miserable death and that is not what genuine hunters are about. The same applies to the WMR's ability to withstand more aggressive weather conditions; the heavier bullet drifts less than the HMR's 17/19grn bullet. Lastly and this is based on my experience with centre fire cartridges rather than rimfire cartridges; lighter bullets will lose their energy at longer ranges far more quickly than there heavier counterparts. My answer to the above comparison is that the two cartridges should not be compared. There are both good cartridges but with different uses. Before purchasing a rifle the shooter should accurately determine its use. If the rifle is intended for small game at longer ranges then the .17HMR should be the first contender. If the rifle is for heavier game and the shooter operates in areas where high winds are the norm then the .22WMR is a better choice. Paul Green Thames Valley Guns www.thamesvalleyguns.co.uk Date: 03 Jan 2011

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