Modern Personal Defense Weapon Calibers 009: The .22 Winchester Magnum Rimfire

Left to right: 5.7x28mm FN, .22 Long Rifle, .22 Winchester Magnum Rimfire, .22 Short Magnum AM180, 9x19mm NATO

So far in the Modern PDW Calibers series we’ve talked about small caliber, high velocity PDW rounds like the 5.7mm FN and 4.6mm HK, and we’ve tackled larger, punchier calibers like the 10mm Norma Auto and the 7.5mm FK. However, we still have not tackled the very extreme low end of the spectrum, that is rounds that are so small and impotent that many question their usefulness as antipersonnel rounds at all. However, small size brings with it some benefits in recoil and round weight, so it’s worth taking a closer look at this kind of round.

The most common round of this type, and one of the most common rounds in the world, is the rimfire .22 Long Rifle, however we will not be considering that round today. Rather, let’s take a look at its big brother, the .22 Winchester Magnum Rimfire. The latter has been more seriously proffered as a personal defense weapon caliber, and almost relentlessly compared to the larger centerfire FN 5.7x28mm round. Versus the .22 LR, it packs much higher initial energy and velocity, and is offered commercially with true jacketed bullets, aiding its penetration especially at longer ranges.

Ballistically, it compares to the 5.7mm FN and 9mm NATO like so:

From a pistol, the .22 WMR seems very much like a tiny pistol round, with similar drop characteristics. Notably, from this short barrel length the .22 WMR seems extremely range limited; it’s doubtful that the round would be a reliable killer – much less stopper – beyond 100 meters. From a rifle, however, the .22 WMR gains about another 200 yards, making it perhaps a useful antipersonnel round out to that distance, provided it is used in quantity. The .22 WMR does not seem to have enough velocity retention from either barrel to provide very much anti-armor capability at all, and it’s notable that the 5.7mm FN has as much velocity at 100m as the .22 WMR does at the muzzle, from a rifle.

No one expected the .22 WMR to be a stellar ballistic performer, however, and its primary benefits lie elsewhere. Like the 5.7mm FN, the .22 WMR has far less recoil than the 9mm NATO, and the .22 WMR is even substantially lighter than the 5.7mm. 40gr CCI Maxi-Mags clock in at 4.1 grams per shot on my scale, by far the lightest round we’ve measured yet in this series, and 37% lighter than the 5.7mm FN.

Considering just ballistics and recoil, the 5.7x28mm is by far the superior caliber to the .22 WMR, and our analysis could end there. However, the .22 WMR does offer the interesting advantages of extremely light weight and extremely small size, which immediately suggests the idea of a small-caliber “bullet hose” designed to carry hundreds of rounds of ammunition in a single magazine and rip them off at thousands of rounds per minute. Something like this:



Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at [email protected]


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  • Jared Vynn

    Bullet hose, like say a rimfire microgun (what comes after micro, nano?)?

    Any chance you will be covering the 22 hornet as well?

    • gusto

      22hornet punched thru my 5mm homemade steel swing-target (:

      • Jared Vynn

        I know a lot of load data for the 22tcm was borrowed from the hornet, and it also puts holes in 5mm/¼ inch steel. Would be an excellent cartridge for a PDW firearm, only downside is the cartridge length.

        • .22 TCM is upcoming, and ballistically it is extremely similar to the Hornet.

  • Bub

    The problem with 22 wmr as a fire hose is the lack of platforms. Savage has a new semiauto, but most other semis are expensive. Plus mag capacity in the 22 wmr is typically 9 or so rounds. Some lever and pump guns will get you a few more rounds, but reloads are going to be really slow.

    • Bucho4Prez

      My first rifle was Remington pump-action .22wmr. Was quite nice, but I was keen to trade for something that shot ammo I could afford.

    • Kyle

      The Keltec CMR and PMR are the best bets for seriously using .22 WMR with significant capacity. The standard mag holds 30 rounds. I’m sure someone will get around to making some big extended monstrosity that holds a bucket full of rounds. The CMR strikes me as a convenient PDW on the market now. It small with a fully collapsing stock, lightweight, barrel long enough to get the most out of the tiny round, good mag capacity and fairly cheap compared to it’s competitors.

      • Bub

        Personally I like the ideal of the CMR. My only concern is reliability issues I’ve read about. Keltec makes some interesting products.

      • Swarf

        Ruger is hinting around at it.

      • valorius

        From everything i read, the PMR-30 is anything but reliable. The last thing you want in a self defense weapon.

  • TheNotoriousIUD

    The .22 F/A seems like the perfect choice for any protection service whose primary aim is to throw a lot of lead very quickly and get their principal off of the X.

    • iksnilol

      Ooor, backpack with belted 5.56 feeding an arm mounted SBR’ed KAC Stoner. You could even have one on each arm and truly hose down everything.

      This is of course not handy for military, but for police who otherwise only have a duty belt to carry, an ammo backpack wouldn’t be unreasonable, especially if it came with arm mounted MGs.

      C’mon, it’s the 21st century, I want W40K already.

      • TheNotoriousIUD

        COUNTERPOINT: Genetically engineer a race of hybrid “Super Cops” who can ingest scrap metal and convert it into bullets which are then fired from their buttocks.

        • iksnilol

          COUNTER COUNTERPOINT: Ingesting scrap metal and shooting bullets from buttocks doesn’t require the arms or back, thus we could have both in the same package.

          360 degree cone of fire, imagine it… no escape.

          • Brett

            Just when I think I have seen the extent of this blogs nerdiness, you guys turn around and make me proud.

        • NEED A DISPENSER OVER HERE

          • Jared Vynn

            Alrighty then. Erecting a dispenser.

        • marathag

          Ah, you mean Tyranids.

          But their ass cannons, aka firing sphincters, just fire smaller bugs.

  • MrBrassporkchop

    I’ve always heard the main issue being rim fire is less reliable than center fire.

    • iksnilol

      Can be solved to some extent with a dual firing pin (instead of striking at one point, it strikes at two opposite sides of the rim. Think a trident with the point in the middle gone).

      • Edeco

        I like the dual firing pin idea, have heard of it before (well, dual strike areas, not two seperate pins) with old open-bolt rifles. Reminds me of dual sparkplug engines which I think are the bees knees.

        But also then there’s the issue of needing more force to crush two areas. And in any case with most rimfires dry firing can cause issues, and they run a little dirty and don’t stack in box mags as naturally.

        • iksnilol

          Dry firing ain’t no issue if snap caps or old cases are used.

          Running dirty is just natural, whilst box mags Kel Tec solved neatly with their PMR-30 mags.

          • Edeco

            Hmmm. I believe accidental dry firing can occur in some autoloaders when attempting to shoot. Natural though it may be the dirtyness probably lowers rather’n raises MRBF.

            Finally while Kel Tec did the nigh-impossible with the PMR mags, I doubt they can ever perform as well as factory glockazine or other premium/mature centerfire mags.

    • valorius

      Eley primed premium stuff is very reliable. I agree with the common wisdom when it comes to bulk ammo though.

    • ostiariusalpha

      There is also the matter of rimfire’s pressure limitations. The .17 WSM has the highest max pressure for a rimfire, topping out at 33,000 PSI, which is well beyond .22 Magnum or .17 HMR; even so, that’s less than the 9x19mm ammo rated for old Lugers. The rimfire casing can only be so thick for being crushed during ignition, and as you’ve pointed out, it is still less reliable than centerfire primers.

  • QuadGMoto

    Apparently the moderator(s) at TFB are busy doing cool stuff instead of checking for trapped comments. Here is mine from this morning, minus the link:

    However, the .22 WMR does offer the interesting advantages of extremely light weight and extremely small size, which immediately suggests the idea of a small-caliber “bullet hose” designed to carry hundreds of rounds of ammunition in a single magazine and rip them off at thousands of rounds per minute.

    In other words, unless something like this was already made prior to 1986, it is illegal for citizens serfs to ever own thanks to the $#%#@, blatantly unconstitutional Hughes Amendment.

    There is a White House petition to urge the administration to eliminate that garbage. I encourage everyone to go sign it (I have) and contact your reps to get ride of the thing.

  • valorius

    .22 WMR is about equivalent to 5.7mm FN ammo from a Five Seven pistol. From a pistol .22 WMR is nowhere near as potent as 5.7mm ammo.

    A .22 WMR rifle is certainly a viable home defense or small game hunting weapon, but i’d never use it for anything but that unless i had no choice.

  • valorius

    As i’ve said in other threads on TFB, Aguila .22 short 60gr SSS ammo is something that could reasonably be considered an effective self defense round. Even from a tiny barreled pistol it will penetrate in excess of 12″ of 10% gel and tumbles end over end on impact.

    I keep the .22 Browning BLR wall hanger lever gun in my guest bedroom loaded with the stuff. (Because what kind of host doesn’t provide his guests a means to defend themselves?)

    If you’re keeping something like a S&W M&P15-22 as your home defense weapon, this round would be impossible to beat, IMO.

    • Charles

      I found the SSS to cycle and fire reliably in my Marlin 60 and Papoose 70 semis and an S&W Victory.22 with a Gemtech GM22 screwed on the end. I was happy to discover that off-hand accuracy @ 50 yards to be surprisingly acceptable also.
      I’ve yet to try it in my TacSol .22 1911 top with-and-without suppressor , or the TacSol .22 AR conversion top with-and-without the suppressor. Sorta wanted to use the Sparrow that’s still waitin’ to get out of NFA lockup before putting too many of those oversized lead slugs and their build-up through the rest of the stable with cans installed. I can only suspect that the extreme exposure of the 60 gr. slugs to transfer huge amounts of lead to a can’s interior, which the Sparrow will make for much easier dismantle & cleaning.

      • valorius

        Through a suppressor the aguila 60 gr sss is holywood quiet, but it does have some nasty smelling noxious blowback gas in that role.

        But…no recoil, eley primed, passes FBI gel penetration protocol, tumbles end over end….the round has a LOT going for it. To me it makes any lever, pump or semi .22 rifle a fantastic home defense weapon.

  • valorius

    .22 WMR is betrayed by high ammo costs. If you’re going to pay a lot for ammo, you might as well buy something more powerful.

  • roguetechie

    George kellgren liked the .22 wmr so much that while at interdynamics he came up with an EVEN smaller caliber bullet for the wmr case and the mkr rifle to fire it including development of a 300 round drum magazine and even worked up techniques mostly seen in extended range artillery to help it retain velocity at range…

    Also in full scale production the projected costs of the ammunition were absurdly cheap!

    • Would love to hear more about this.

      • I have a ton of data on the 4.5x26RF. I might actually be able to do one for the MPDWC series.

        • I just looked up the MKR assault rifle, and now I’m not sure if I’m nominating that or the Steyr ACR for “ultimate gun that never was, that I must have.” Absolutely would like to see your ballistics charts on it.

          Also, what PSI is the 4.5×26 running at? From the specs, it’s going faster them Elite’s S4M 5.7 load, which launches the SS195/SS198 27gr aluminum core projectile at 3,000 ft/s from the PS90.

          I believe they are running in the neighborhood of 48-50kpsi, so if the 4.5×26 is exceeding that with a .22 magnum sized case, it must be using either magic engineering or very high pressures.

          • demophilus

            IIRC, the “magic engineering” on the MKR was a longer barrel than the PS90. Wikipedia has the barrel at 600mm — UIM, that’s 23 inches, some of it bullpup for a short OAL.

          • 4.5x26R was running at like 70,000-80,000 PSI. Truly nutso burrito.

        • Giolli Joker

          Comparison with .17 HMR would be good too.

  • It’s funny you mention the American 180 – I’ve thought for a while how cool it would be to have an American 5.7 – an American 180 in 5.7×28 with a 200rd pan magazine.

    Sort of a HackSAW meets PDW for urban fire suppression.

    Since 5.7×28 works in a blowback P90, shouldn’t be the hardest project to pull off.

    • valorius

      I always thought a true manportable 5.7mm minigun would be really, really EPIC AND COOL AS HELL!

      • That would be extremely cool. Perhaps mounted on a mini, motorcycle sized quadcoper drone, along with a few of those 2lb Ratheon Pike missiles.

        Well, at least until it’s hijacked by Skynet, it would be cool….

  • Goody

    cmr30 is a more modern 22wmr PDW candidate, and one I’d consider if I was allowed a full auto limited to only one cartridge.

  • They made them, yes.

    I’m familiar with the Knox Engineering concept. Word on the street was he was blowing up his test barrels. Ouch.

  • I have some docs on the MKR as well.

    • roguetechie

      You gave me the one 15 or 16 page PDF already, however it’s missing the diagram…

      Really want this diagram should you come across it, oh yes please and thank you in advance should you find it!

    • roguetechie

      Specifically mkr rifle 21 .jpeg

      I have page 20&22 but 21 is missing….

      Got a nice look at the front of the gun but the back end where the fun stuff resides is sadly missing…

      It’s like nekkid ladies with pasties… So close to exciting that it just winds up being frustrating lol

  • Amplified Heat

    What, no idiots claiming 5.7×28 is a “glorified 22WMR” around here? Where’s that MAC video showing a PMR30 and five-seven having similar performance on gelatin & kevlar? Going by the numbers here, such demonstrations don’t quite seem consistent with basic physics…

  • Howard

    After reading the linked document, I must admit my interest is piqued and would like to know MORE!
    Not that I am much more than an acquirer of esoteric firearms/ammo doo hickies, the KEK H.E.C. seems like it had much to recommend it and yet NUTHIN’!
    Why? Inquiring minds wanna know.
    TIA for any info or links you have and could provide.