17 HMR
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The .17 HMR Rifle Cartridge: All the Details You Ought to Know

The .17 HMR is quickly becoming a popular round. Here are a few things you should know about it.

The .17 Hornady Magnum Rimfire, or .17 HMR, was developed in 2002 by the Hornady ammunition company.

It is the one of the hardest-hitting and most accurate rimfire rifle cartridges available today.

Let's take a detailed look at the increasingly popular .17 HMR ammunition.

.17 HMR Specs

  • Parent Case: .22 WMR
  • Primer: Rimfire
  • Overall length: 1.349 in (34.3 mm)
  • Case length: 1.058 in (26.9 mm)
  • Bullet diameter: .179 in (4.5 mm)
  • Base diameter: .238 in (6.0 mm)
  • Rim diameter: .286 in (7.3mm)


Although it is the child of the .22 Winchester Magnum Rimfire, the .17 HMR was one of many attempts to recreate the ballistics of the 5mm Remington Magnum Rimfire. The RMR was produced during the 1970s and at the time was the fastest rimfire cartridge available.

With RMR barrels and ammo near impossible to find it was discontinued in search of an easier-to-produce alternative.

The .22 WMR casing was chosen over the RMR because it requires a special bolt and magazine. The WMR casing was also more readily available as well as larger and stronger than other .22 LR. With this casing a simple barrel swap was all that was needed to produce weapons capable of firing the round.

Although the .17 HMR blows past the muzzle velocities and trajectories of the RMR and WMR, its downrange energy potential is still less than than the RMR. This still leaves an area open for further production of an even more powerful rimfire round in the future.

The first HMR rifles and ammo hit the market in 2002. Rounds are available in hollow point, soft tip and FMJ from numerous companies.

.17 HMR Pros and Cons


  • Faster flight path
  • Longer-range capabilities
  • Flat trajectory
  • More accurate


  • More expensive than other rimfire ammo
  • Less kinetic energy
  • More destructive at close range
  • Considerably louder

While this round is a little much for varmint hunting or small game like squirrel and rabbit up close, it is perfect for taking down larger animals such as raccoon, opossum and fox. Long-range prairie dogs with an accurate bolt action rifle would be great for the .17 HMR, just not too long of a range.

There have been videos of people using them to take coyote and hogs, but unless it's within 50 yards and a very well-placed shot it is not recommended by any manufacturer.

Speaking of, lots of ammo makers have hopped on the HMR train, beyond just Hornady. Federal, CCI, and Winchester make some rounds that are among our favorites.

All in all, small game hunting and the shooting sports got a nice addition to the collection when the .17 HMR emerged, and since then they've been right at home in the magazines of plenty of firearms.