Tandemkross (TK) is an American manufacturer dedicated to providing its customers with a variety of competition-grade components for popular semi-automatic rimfire pistols and carbines. The gun brands they support include Ruger, Smith & Wesson, Taurus USA and Walther Arms, to name a few. Over the last few years I've enjoyed the results of incorporating TK products into at-home rimfire build projects, especially those based on the Ruger 10/22 platform.
TK now offers all of the components to assemble a competition-grade 10/22 platform.
But until recently, TK did not offer all of the parts needed to build either a 10/22-pattern carbine or pistol. Most notably absent from its catalog was the serial numbered receiver that is the foundation of all 10/22s. But in 2025 things changed with the introduction of the TKX22 receiver which is CNC-machined from a billet of 6061-T6 aluminum. Designed for use with fixed barrels, it features an integral 0 MOA Picatinny optics rail, an easy access cleaning port and a durable matte black hardcoat anodized finish.
With the TKX22 receiver in hand, along with this company's innovative Manticore X lower assembly, it's now possible to build a ready-to-shoot carbine or a Charger-style pistol using what TK has in stock. The key difference will be which barrel length you choose. This company offers the 16" long light-weight Spitfire barrel, for carbines, or the shorter 10.2" Comet barrel pistol builds. In this case, I opted to assemble a large format .22 LR “Comet Pistol” using TK products.
The Manticore X fills a variety of roles, much like an AR-15 lower receiver.
This project began as a set of loose parts shipped directly from TK. The exception to this was the serial-numbered TKX22 receiver. Because this component is federally regulated as a “firearm,” it was transferred through a local FFL dealer with the requisite ATF Form 4473. Otherwise, the parts needed for a complete pistol were there in the box.
TK's Manticore X “lower” simplifies the 10/22 part selection and assembly process a good deal. This is because it's fully outfitted with hardcoat anodized, competition-style controls at the factory. The CNC-machined aluminum chassis houses the trigger group with extensions and modifications that eliminate the need for a shoulder stock by holding the action together and providing a magazine well. The housing is designed to be used with a removable AR-15 style pistol grip. At the rear of the Manticore X is an extension that supports a short Picatinny rail for attaching fixed or folding stabilizing pistol braces. The Manticore X ships with a set of ball detent cross pins, to secure it to the receiver, and a rubber Shock Block bolt buffer.
The completed Comet pistol is 18.25” long and weighs 2 lbs. 12.8 oz. before adding the optic and brace.
The 10.2" long Comet pistol barrel is designed to be lightweight and accurate. The slim stainless steel barrel is set into a vented aluminum shroud with the muzzle secured by a nut that is tightened to hold the barrel in tension. This in turn makes the barrel ridged so as to reduce vibration. The muzzle is threaded at ½ x 28 TPI for attaching popular muzzle devices including compensators and sound suppressors. The aluminum thread protector rests atop a rubber O-ring to keep it from shaking loose.
The barrel was secured to the receiver using TK's aluminum V block and a pair of Rim/Edge V block screws. Although it was not mechanically necessary to do so, I went ahead and installed a light weight aluminum Manticore X M-LOK handguard. Slimmer and shorter than the barrel, this guard looks sharp and provides a useful support for attaching a bi-pod or resting the pistol against sandbags when shooting from the bench.
The tensioned Comet barrel and the aluminum handguard are both vented to reduce weight.
The interior of the receiver was outfitted with a hardened-steel KrossFire bolt assembly. Designed for speed and durability, it ships with the upgraded Eagle’s Talon Extractor, a Fire Starter Titanium Firing Pin and a sleek black PVD coating. The Spartan Skeletonized Charging Handle assembly features an oversized and hollowed out aluminum extension that is available in red (shown), black or silver anodized finishes. The pistol was completed with the AR-15 type hiveGrip. This polymer grip sports a hand-filling, finger-grooved and textured rubber surface that is ideal for precision shooting. It also has a removable base plate with a water-resistant seal so that the grip's hollow can be used as a storage compartment.
The Midwest Industries aluminum folding stabilizing brace is built to be durable and light weight.
This project was capped off with TK's unique DoubleKross 20-round magazine. Built with a translucent polymer housing, this magazine is essentially two 10-round rotary magazines welded together at the base. This makes for an exceptionally reliable and compact unit that does not get in the way when shooting from a bench rest.
The competition style extended controls are made of aluminum and anodized to match the red barrel shroud.
When fully assembled, the Comet pistol tipped the scales at 2 lbs. 12.8 oz. with an empty magazine before attaching the brace and optic. The fit and finish was top shelf throughout. The red barrel shroud V block, extended bolt catch, bi-directional Fireswitch magazine release lever, ambidextrous safety levers and flat-faced trigger provide a handsome contrast to the matte black finish of the rest of the gun. The trigger of the adjustable Ultimate Trigger Kit, sporting a flat-faced Victory trigger shoe, arrived tuned to a 2 lbs. 14 oz. trigger pull. It exhibited a crisp, clean break after just an eighth of an inch of travel.
At the shooting range the TK Comet proved to be a reliable operated with sub-one-inch accuracy potential.
For the shooting evaluation, two aftermarket upgrades were added to the Comet pistol. A Swampfox Kraken enclosed-emitter 3-MOA red-dot ($349) was mounted to the optics rail for informal and formal testing. The rear accessory rail was used to support a tough, American-made Midwest Industries Inc. folding Arm Brace (MI-ARM-SF; $209.95). Its high quality construction and feature set has made this one of my favorite stabilizing braces to work with.
In addition to the DoubleKross magazine provided with the parts set, the Comet was tested using Ruger BX-10, BX-15 and a BX-25 factory magazines. I also threw in an old Butler Creek Hot Lips 25-round “banana” magazine to keep things interesting. All of the magazines fit and fed properly with the loads of ammunition tested.
A Garmin Xero C1 Pro chronograph was on hand to track the average muzzle velocity of the rounds tested.
Semi-automatic pistols chambered for 22 LR can be ammunition sensitive in two ways. The first is reliability. I've shot pistols that would not cycle with certain ammunition brands or bullet weights. In the case of this pistol, it fed, fired and ejected all of the brands and bullet weights tested. There was a single failure to eject and one bad primer across the hundreds of rounds fired. Both of these malfunctions indicated an ammunition issue, not a gun issue, and they were simply par for the course when using bulk-box loads.
The best individual 5-shot group of 0.75” was fired using the Remington load.
Once you’ve found the loads that run reliably, the next issue that can crop up is accuracy. Even with a high quality pistol and a longer barrel, like this one, the quality, velocity and bullet type of the ammunition fired can cause notable shifts in accuracy. Loads that can keep 5-shot groups in and around 1.5 inches in size at 25 yards are doing just fine. Those were the averages with the CCI Target and Winchester Wildcat loads used for the formal bench rested testing. But in this case, it was the slower Remington Standard V that exhibited sub one inch group potential. A Garmin Xero C1 Pro chronograph was on hand to track average muzzle velocity for 10-shot strings. Here are the complete results:
Building a Tandemkross custom pistol like this has been on my bucket list for a while now. And I have to say, it did not disappoint! If large-format .22 LR pistols are not quite your style, know that all of the upgrades and features incorporated into this pistol project are available for a carbine build. Just order a 16" barrel and a shoulder stock instead! For more information, visit tandemkross.com.
Tandemkross Custom Comet Pistol Specifications:
Component Provider: Tandemkross (TK)
Action: blow-back operated; semi-automatic
Caliber: .22 LR
Upper Receiver: TKX22, matte black (TK18N0569BLK1; $164.99)
Barrel: 10.2" Comet, tensioned stainless steel, 1:16 RH Twist, red aluminum shroud, ½ x 28 TPI threaded muzzle, 8.2 oz. (TK18N0561RWS1; $259.99)
V Block: TK aluminum, red (TK18N0449RED1; $19.99)
V Block Screws: Rim/Edge 2 Pack (TK18N0453BLK1; $5.99)
Handguard: Manticore X M-LOK, aluminum, black (TK18N0531BLK1; $59.99)
Bolt Assembly: KrossFire, black (TK18N0122BLK1; $139.99)
Charging Handle: Spartan, skeletonized, red (TK18N0121; $31.99)
Lower Receiver: Manticore X, red appointments (TK18N0511RED1; $499.99)
AR-15 Pistol Grip: hiveGrip, black (TK11N0371BLK1; $39.99)
Magazine: DoubleKross, 20-rounds, fully assembled (TK18N0105CLRA; $49.99)
Sights: None, optics rail
Trigger Pull: 2 lbs. 14 oz. (as tested)
Overall Length: 18.25" (no brace)
Weight: 2 lbs. 12.8 oz. (with empty DoubleKross magazine)
MSRP: $1,302.90 (as configured, not including shipping and sales tax)
