In 2021, Rock Island Armory shook things up in the defensive-pistol world when it launched the STK100, a striker-fired 9 mm pistol with a frame made from aluminum instead of injection-molded polymer. For 2022, the company continues its commitment to “Total Metal” firearm construction with the TM22 rimfire rifle. Some have described the blowback-operated, semi-automatic TM22 as an AR-pattern rimfire, but this is not a wholly accurate description of the platform. Although the rifle does incorporate a number of AR-compatible components, it does not mimic the appearance, feel, controls or operations of an AR-15 as do the Smith & Wesson M&P 15-22 or Tippmann Arms M4-22 series of dedicated .22 Long Rifle semi-automatic carbines.
Nearly all of the components are made from either steel alloys or 7075 aluminum treated with matching matte-black finishes. The only exceptions are the polymer AR-15-type grip, magazine followers and magazine baseplates. The receiver separates into two pieces, but not in AR fashion. The top of the receiver consists of a cover plate and 7.5"-long optics rail milled from a single billet of aluminum. The rail extends past the receiver to support a screw that secures the aluminum handguard in place.
The rest of the receiver is a monolithic unit, including the trigger guard. The upper portion of the receiver features right- and left-side slot-shaped ports; the right is the ejection port, and the left-side slot accommodates the charging handle, which is mounted directly to the bolt assembly. This reciprocating handle is knurled for improved purchase, but it cannot be moved to the right side of the receiver.
The grooved aluminum safety lever is mounted to the left side of the receiver directly above the pistol grip. The safety swings up into the Fire position, exposing a red dot on the receiver, and down into the Safe position, uncovering a white dot. It’s easy for right-handed shooters to operate using the shooting-hand thumb, with a distinctive click when pressed into either position.
A checkered, round-button magazine release is located on the right side of the magazine well. The well is configured to accept proprietary, single-stack, aluminum magazines. These magazines are a clamshell design with a curved profile and a removable polymer baseplate. It’s a sturdy design for a rimfire rifle, especially considering that most magazines in this class are made with polymer bodies. The rifle ships with two 10-round magazines fitted with followers that hold the bolt open when the last shot is fired.
The straight, flat-faced, aluminum trigger exhibited a very light 2-lb., 1-oz. pull, according to a Wheeler Engineering digital trigger gauge. It has a smooth, clean feel that swings past an indistinctive break and continues to travel until it comes to a stop against the rear of the trigger guard. While it does not offer the crisp break of a target-shooting trigger, it’s pleasant to use once the shooter becomes accustomed to it.
The AR-pattern polymer pistol grip is overmolded with lightly textured and finger-grooved soft black rubber. It has a slim profile and grippy feel that makes it quite comfortable to work with. For those who prefer other grip styles, the rifle can be fitted with a variety of aftermarket AR-15 options.
Rock Island Armory is offering two versions of the TM22, one with an 18" barrel (which was used for this evaluation) and one with a longer 20" tube. Our test gun’s 0.75"-diameter muzzle was threaded 1/2x28 TPI to support a variety of popular .22-cal. muzzle devices, including flash hiders, compensators and suppressors. A knurled steel thread protector is provided.
The 10"-long free-floating aluminum handguard is well-ventilated with M-Lok accessory slots along the 3-, 6-, 9- and 12-o’clock positions. Although the handguard is supported by an AR-15 barrel nut and looks like an AR part, it is a proprietary component. Because it is secured by the extended optics rail, it cannot be swapped out with aftermarket handguards.
A fluted aluminum AR-15 buffer tube is set into a threaded port in the receiver and secured in place by an AR-15 endplate and castle nut. The endplate provides a left-side sling loop. The buffer tube is then capped with a skeletonized, textured buttplate with a curved toe, for a 13" length of pull. Because the recoil assembly is wholly contained inside the receiver, the factory-installed buffer tube can be traded out with other AR buffer tubes to support both fixed and adjustable shoulder stocks.
Although a good number of centerfire rifle designs are fairly easy to break down for cleaning and maintenance, it seems like rimfires often require additional steps. The TM22 is no exception to this unwritten rule—its takedown includes the removal of three receiver screws, the handguard, the barrel nut and the barrel, and then unscrewing the bolt-mounted charging handle. Once these steps are complete, the top of the receiver can be lifted off to provide access to the bolt and recoil assemblies.
With an empty 10-round magazine installed, this all-metal rifle has an unloaded weight of 5 lbs., 15 ozs. The balance point is located right at the barrel nut, giving it a handy feel with an easy swing. Its sleek lines, features and finish give this rifle an overall appearance that belies its $348 suggested retail price.
For our range test, the TM22 was topped with an affordable Bushnell Rimfire 3-9X 40 mm scope with a DZ22 Drop Zone reticle. It’s not uncommon for rimfires to be more finicky when it comes to ammunition selection; our TM22 experienced half a dozen failures to feed when using standard-velocity target loads. However, all high-velocity brands (1,200 f.p.s. or more) and bullet weights operated reliably without any malfunctions during the test.
The Rock Island Armory TM22 rifle offers a refreshing take on the popular .22 LR platform that provides a familiar profile without simply cloning an existing design. It is a solidly built gun with a smooth action, light trigger and reliable design. It succeeds in being different from the competition, while incorporating the modern rifle features many rimfire fans are looking for at a price that won’t break the bank.
