Rimfire rumblings

Rimfire rounds rarely get a lot of notice, which is unfortunate.  Lower velocity rimfire cartridges often make great training and plinking rounds, while faster loads are great for pest and varmint control.  However, some rimfire cartridges now equal centerfire velocities and others are providing a credible service for self-defense.


Smokin’ Fast Rimfire

What’s the fastest production rimfire cartridge on the planet?  The new .17 Winchester Super Magnum (WSM).  How fast is this new round?  Try 3,000 fps!

Winchester Ammunition announced earlier this year the development and introduction of the .17 WSM cartridge that they claim is the fastest rimfire around.  According to the company, with the speed there are improved wind drift and bullet drop characteristics, plus a 150% increase of energy dump into the target.

Initially, Winchester is offering the .17 WSM cartridge in three different loads.  The first round uses a 20 grain Varmint HV, polymer-tipped bullet that makes for the legendary 3,000 fps.

The second load is from the Super X line.  It uses a 20 grain conventional JHP bullet.  Muzzle velocity specifications are not published for this load, but the ballistic charts puts the 50 yard velocity at 2641 fps – slightly slower than the 20 grain Varmint HV load.  That load shows a velocity of 2745 fps at the same distance.

The third load is listed in the Varmint HE (high energy) line and uses a 25 grain, polymer-tipped bullet.  This round has a muzzle velocity of 2,600 fps.

Of course, a rimfire that is generating centerfire-like velocities is also generating high chamber pressure.  Consequently, rifles that are designed for other rimfire cartridges are not likely to be converted for .17 WSM use.


Savage introduced a new rifle called the B.Mag.  The new gun is a bolt-action rifle of an entirely new design.  It does not share any of the parts from the company’s existing line of rimfire rifles.

Savage BMAG rifle
Savage BMAG rifle

The Savage B.Mag rifle has a short-action bolt that cocks on close, and has rear locking lugs to help safely manage the pressure.

The B.Mag rifle shares a number of features with the company’s centerfire rifles including the highly-regarded AccuTrigger that allows the shooter to make adjustments without any need for specialized tools.  The gun also uses a thread-in headspacing system, which is similar to the design used by Savage to improve the accuracy of their centerfire rifles.

MSRP on the rifle is $349 and it should be shipping soon.

The Old Magnum

Until the 17 HMR came along about 11 years ago, the 22 Winchester Magnum Rimfire (aka 22 Magnum or 22 WMR) was king of the rimfires.  While this straight-walled cartridge may seem somewhat pedestrian compared to the new, higher-velocity rimfires, it isn’t ready for pasture quite yet.

In fact, the 22 Magnum has seen a lot of recent development in the self-defense market.  The North American Arms (NAA) mini-revolvers in 22 Magnum have been a popular choice for many people looking for an ultra-concealable handgun.  But, new options in guns and ammo have been developed in recent years.


Earlier this year, Ruger brought out a new version of their polymer revolver chambered for the 22 WMR.  The new LCR-22MAG is the same general size as the other revolvers in this line, though it is slightly heavier at 16.6 ounces unloaded.

Ruger LCR-22MAG-R

For someone who needs a light-recoiling revolver for self-defense, this is definitely a good option to consider.  It comes with Hogue Tamer rubber grips, and I’ve found the .38 Special versions of the LCR to be easier recoiling than my Smith & Wesson J-frame.  MSRP is $529.

If you are relying on the 22 Magnum for defense, there are now some premium ammunition lines that include loads for this mighty rimfire.  The most recent addition is the Winchester PDX1 Defender load that uses a 40-grain JHP rated at 1295 fps.  Unfortunately, I do not know at what length barrel this was measured.

In 2012, Speer added the .22 WMR to the highly respected Gold Dot line of ammunition.  This cartridge uses a 40-grain bullet also.  From a 1.9” barrel, Speer measured muzzle velocity at 1150 fps.  The company also stated that consistent penetration of 10-11” was obtained when using barrels as short as 2”.  For a rimfire shot out of a short barrel handgun, that is not bad.

Hornady loads a self-defense round for the 22 Magnum in the Critical Defense line.  This load uses a 45 grain FTX bullet, which is a polymer-tipped hollow-point.  From a 1 7/8” test barrel, Hornady measured velocity at 1000 fps.  When shooting the load from a Smith & Wesson 351PD revolver with a 1 7/8” barrel, penetration measured between 9-10”.  Testing of the Critical Defense line of ammo has shown these rounds generally do a very good job of expanding, even through various intermediate barriers.


If you are looking for a great varmint round or a viable self-defense tool, the rimfire cartridges might have what you are looking for.  Innovation continues, and I expect we will continue to see performance increases in rimfire rounds in the future.

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