Still Holding On: .22 AutoMag II Magnum Rimfire Auto


by Paco Kelly

photography by Paco Kelly

Updated August 9, 2006




It wasn't very long ago that some very well-designed little .22 Magnum handguns were available from AMT (Arcadia Machine & Tool) of Irwindale, CA.

The two auto handguns pictured in the accompanying photos, the 4" barreled version and the 6" barreled version, were purchased years ago. These guns, along with a 2" barreled version, were still listed in the 2000 Guns & Ammo Annual, but they had unfortunately disappeared by the time the 2001 G&A Annual was published.

You won't find too many auto-loading .22 Magnum handguns on the market because of the difficulty in the blowback systems typically seen in auto-loading rimfires. The extra pressure of the .22 Magnum requires a very heavy and bulky slide as an inertial damper, but AMT wanted to keep their guns slim, trim, attractive and appealing. SO to overcome the problem of blowback before the bullet leaves the barrel, AMT showed a little bit of design genius...

The AutoMag II's chamber has a series of small indents in its chamber walls. Upon firing, the cartridge case expands into the indents as well as against the chamber wall, thus gripping the wall of the chamber. By the time the chamber wall has been released by the brass' "memory" springing back to its normal state, the bullet has left the barrel, pressure has dropped to a safe level, and the ejection cycle continues as normal. AMT always explained in their user manuals, "USE ONLY .22 WINCHESTER MAGNUM RIMFIRE AMMO".

When the AutoMag II first hit the market, CCI .22WMR ammo wouldn't completely activate the slide in the ejection cycle. This would cause jams. Winchester brand ammo did not exhibit this problem, which probably resulted from differences in the brass recipe used in the cartridge cases. These problems were rectified in a very few years, and CCI ammo, as well as Winchester and several other makes, now cycles just fine in my two guns.

The 4" barrel model is actually a bit more than that if measured from the breech face with an empty chamber. Dropping a measuring rod down the barrel (after double-checking that the gun was not loaded!) yielded a measurement of 4.57", which would drop to a bit less than 4" from the nose of the bullet once the gun is loaded.

But in truth, we should measure to the mouth of a fired cartridge case, because the pressure begins at the base of the bullet, not the nose. With revolvers, the "real" barrel length, as far as pressure is concerned, is from the mouth of the cartridge in the cylinder's chamber all the way to the muzzle of the barrel.

So, measured in this way, the AMT's barrel is actually very close to its advertised 4" length. Plus it is a "closed chamber", unlike a revolver which has a barrel/cylinder gap that drops 50-60 feet per second of muzzle velocity for each 1/1000th of an inch in the gap. For comparison, centerfire cartridges such as the 9mm, .40 S&W, and 10mm Auto lose nearly 100 feet per second for every 1/1000th of gap.

The AMT AutoMag II's slide is 0.791" wide, or just a little over 3/4" of an inch. The grips are just slightly over 1" wide. The average .45 ACP autoloader's slide is an inch wide, and the grip almost an inch and a half. Overall, the 4" AutoMag II is 7" long and 4.8" high.

Small, slim and light to carry, with a nasty bite. Except for grips and springs, the AutoMag II is made entirely from stainless steel. Even the magazine, which holds nine rounds (allowing a total capacity of ten rounds including one in the chamber) is made from stainless steel. The AutoMag II features an excellent hammer block safety, almost Ellison-like adjustable rear sight, and an outstanding ramp front sight.

With most magnum handgun cartridges, there is about a 300-400 fps velocity drop as compared to the same round fired from a rifle, and the .22 Magnum is no exception. Winchester's 40-grain Hollowpoint gives 1903 from my 24-inch CZ rifle; the same ammo from my six-inch AMT clocks 1442 fps, and the four-inch AMT gives 1333 fps.

Rimfire magnum ammo is somewhat strange: it's all over the place in bullet weight, velocities and bullet strength. As an example, for years Winchester used a slow-burning powder in the .22 WMR because the thinking at the big red "W" was, "It's a rifle cartridge". Likewise, CCI used faster-burning powder because they thought of the .22 WMR as a handgun cartridge.

It was Ruger that finally debunked the idea that the .22 WMR was a "rifle-only" cartridge with their wonderful Single-Six with dual .22 LR and .22 WMR cylinders. Up until that time it was only CCI and Winchester with hollowpoint and solid-bullet offerings, but the round I once referred to in an article as "the sleeper" has awakened in the minds of the shooting public and the ammo companies.

As shown in the accompanying picture, there are seven different selections from six different manufacturers, and that's only a small sample of what's available. Some .22 WMR ammo, like CCI's TNT Maxi-Mag, features an extremely explosive bullet design and is tailored more for vermin and pests than for small game. On the other end of the spectrum, some feature extremely tough bullet designs, such as CCI's Golden Hollow Point load, which is loaded with Gold Dot bullets; I have not cut one of these open yet, but I suspect they are solid soft copper with a punched hollow point. Loads such as these are excellent for small game up to javelina and coyotes. Of course, coyotes get hit with everything, whether it's frangible or not!

Remington's Premier ammo has a rounded pointy bullet with a small soft point. Predators have a soft point and a flat tip; this is a jacketed bullet, not a copper-washed bullet, with a large soft flat nose. And of course, all the ammo companies make solids as well as hollowpoint designs. Federal even has an all-lead 50-grain low-velocity load (about 1450 fps from a rifle) for squirrels and such. And much, much more.

I carried RWS (Dynamit-Nobel) European .22 WMR ammo for self-defense when I carried the little AutoMag II off-duty or in the woods and such. It left the barrel of my six-inch gun at an amazing (for then) 1550 fps and 213 pounds of muzzle punch. One day an idiot pulled a knife on me when I informed him that he was under arrest; I put the AMT to his kneecap and pulled the trigger. He fell down and cried for momma, poor baby. The State gave him free room and board for fifteen years, and he gave up dancing forever. But RWS ammo is expensive, so I now go with the CCI Gold Dot. It does just as well, if not better, with its 1525 fps from the 6" AMT.

But to put it in perspective, the .22 WMR from a rifle is much closer to the .22 Hornet than it is between the Hornet and the standard .22 LR high-velocity round. So from a handgun with a four-inch or longer barrel, the .22 WMR will give the same or more velocity than a high-velocity .22 LR will give from a rifle!

The .17s may be all the rage today, but it's the .22 Magnums and their heavier bullets that will bring home the bacon.

Paco Kelly


The AutoMag is back! They are now being produced by High Standard in either 4-1/2" or 6" barrel length. Check them out at

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Click pictures for a larger version.


AMT's AutoMag II .22 Magnum pistol.



The .22 Magnum, or .22 WMR (Winchester Magnum Rimfire) has a wide variety of quality factory ammunition available, including the small sample shown here. The .22 Magnum is still a very effective round for a variety of uses, from target shooting to vermin shooting to small-game hunting and even self-defense, and the AMT AutoMag II was one of the finest .22 Magnum handguns ever produced.