Not only are the favourable running costs tempting, but young people and newcomers can also be introduced to the fascination of shooting sports with fewer side effects. The advantages lie in the almost identical hand position and operation as with the centerfire original pistol. The trigger qualities are also the same and you only need to invest money once for trigger tuning. However, should the basic gun ever fail, you will also have to stop using the conversion kit for the time being. All rimfire conversion kits use a blowback system, which is quite simple and cheap to produce in technical and financial terms. However, the devil is in the details, as the rimfire cartridge is not exactly easy to feed and the wide range of ammunition available on the market varies greatly in terms of muzzle velocity and recoil.
Details of the Marvel Precision conversion kit for 1911 and 2011 pistols
The brainchild of Bob Marvel (Bob Marvel Custom Guns), the Marvel Precision conversion kit for 1911 or 2011 pistols is available for guns with a classic slim single-stack frame or with a voluminous "high capacity" double-stack frame, and is now manufactured by the US company Frerking Custom Works (FCW). It is known for its high quality, functional reliability and precision. With the large number of 1911/2011 manufacturers, there are tolerances in production, which means that minor adjustments may be necessary when fitting the lower frame and the Marvel upper. In the case of our STP Sentry, however, after a quick look at the operating and assembly instructions, we were able to start "plug & play" straight away. Marvel offers two versions of the conversion kit, made from a high-quality 7075 aluminium alloy or from heavy steel respectively, with the latter weighing around 115 to 140 grams more depending on the version. The aluminum version has a steel insert in the area of the breech face and the firing pin channel behind it, which certainly contributes to its durability. Both the aluminum and the steel version of the Marvel upper are fitted with a 5.25" (132 mm) long barrel featuring a conventional rifling, with a neat recessed crown muzzle. The barrel protruding from the slide is also available with a ½"x28 muzzle thread for an additional charge.
In addition to the deeply recessed micrometer rear sight and target front sight, it is also possible to mount a red dot on the Picatinny/Weaver rail. Since the aluminum mounting rail is securely connected to the barrel and frame via the slide stop lever, there is no need to worry about reliable operation with a red dot sight: it is completely isolated from the gun's kinematics. The Marvel conversion kit leaves a clean impression in terms of workmanship and finish. We only have one small point of criticism: the magazines do not have a load assist button that can be pulled down from the outside with the thumb. This makes inserting the ten rimfire cartridges into the polymer magazines a little fiddly. Marvel does offer a small loading aid as an accessory, which is inserted on the magazine front and pushes the already loaded cartridges downwards. The manufacturer promises 5-shot groups of less than 25 mm at 50 m, and each conversion kit also comes with a corresponding test group target as proof of this guarantee. The price for the kit with "Combo Rib" (adjustable sights plus scope mount rib) is $585 (MSRP in the US). If you want the steel kit, you have to spend around $780. An additional magazine costs around 40 bucks.
CZ Kadet conversion kit for the CZ Shadow 2 in detail
CZ recognised early on that a variant of the Model 75 chambered for the popular .22 Long Rifle rimfire cartridge would be a lot of fun for shooters and generate sales for the manufacturer. For a long time, the Kadet was therefore available in .22 LR as a complete pistol and as a conversion kit. Unfortunately, production of the Kadet conversion kit for the original CZ 75 as well as for the CZ Shadow 1 has been discontinued. Currently, the product portfolio only includes those for the successor CZ Shadow 2 or the CZ P07 and CZ P09 polymer pistols.
The Kadet action for the CZ Shadow 2 is made entirely of aluminum alloy – even in the breech face area – and accommodates a 125-mm barrel with a conventional rifling. The slide is in two sections and fitted with a barrel-mounted front sight carrier, presumably to minimise moving masses. This provides functional reserves and it can also be used with the wide range of standard ammunition available. In order to better adapt it to different rimfire cartridges, three recoil springs are included. The factory-fitted silver recoil spring is intended for standard ammunition, the red spring for HV ammunition and the blue spring for weak ammunition. The sights are the same as the centerfire original gun, which means that the change in the point of impact can be easily corrected with a screwdriver. Unfortunately, adjusting the rear sight laterally requires drifting the entire sight sideways, which can be quite a tedious process. Mounting a red dot sight on the slide is also not possible, and the added weight could potentially impair function. This could be remedied with a grip/frame mount, such as that offered by the German manufacturer MAK with its P-Lock mount. The polymer magazines, which hold ten rounds, can be easily filled using the button on the side. The manufacturer also includes an additional one so that the fun can last longer. If that's not enough for you, you can add an additional reserve magazine at a very favourable price of 22 euros. The Kadet conversion kit for the Shadow 2 costs €834 (RRP).
Marvel Precision and CZ Kadet .22 conversion kits on the shooting range
We selected a dozen types of ammo, which were divided fairly into half as standard and half as HV cartridges. The best accuracy result with the STP/Marvel combo was achieved with the 24 mm RWS Semi Auto. In the end, the 10 at 25 m could be hit with every load. And now to the Kadet conversion kit: it shot similarly well and delivered its best result with the RWS Club, at 23 mm. Of the twelve loads, only one was over the 50 mm mark.
The accuracy tests were followed by some dynamic drills, which were not only fun, but also allowed better conclusions to be drawn regarding functional reliability. While the Marvel kit performed flawlessly until the end, the Kadet conversion kit experienced a misfire with the Aguila Interceptor cartridges, but this was probably due to the ammo. In addition, the RWS Club cartridge experienced an extraction problem, and with the SK Semi Auto, a cartridge ejected from the magazine during feeding and became stuck in the ejection port. Ultimately, it's crucial to thoroughly test your preferred ammunition in your own firearm – and with all available magazines. As is so often the case, the devil is in the details, and a malfunction is always a highly frustrating event in competition.
Conclusion from the test of Kadet for CZ Shadow 2 and Marvel Precision for 1911/2011 conversion kits
Rimfire conversion kits can be a welcome addition to training and competition and reduce ongoing maintenance costs. With regard to the last point, however, depending on the purchase price, it can take a five-figure number of rounds before the investment in such a .22 upper pays for itself.
Further information on the Marvel conversion kits is available on the manufacturer's website. You can find out more about the CZ Kadet kit on the CZ product website.
