The appeal of rimfire conversion kits
Oleg Volk 07.29.13
The price of a good conversion kit, such as the Iver Johnson M1911-22 slide shown or the Twisted Industries slides for Keltec and Ruger pistols is pretty close to the cost of a whole dedicated .22 pistol. Yet their popularity has risen sharply in the last several years. There are several good reasons for this.
More and more shooters have figured out that guns without training aren’t very useful. At the same time, the availability of affordable centerfire ammunition has declined. Even with the current shortages of rimfire cartridges, it’s easier to afford a bring or 22LR than to get a case of 45ACP. Further, a lot of youngsters and women have joined the field formerly held mostly by adult men. The relatively heavy recoil of .40 and .45 caliber pistols proved a challenge for many novices who lacked the technique to compensate for smaller hands and less strength. Shooting a quieter, less punchy rimfire variant of the centerfire gun made for more effective learning early on.
Some pistols are available in nearly identical centerfire/rimfire configurations. Bersa 380/22 is a popular choice, Smith&Wesson M&P 9/40/22 is another. Some companies also make rimfire versions of M1911. However, those cost more than just the conversion slide. Conversions also guarantee that the trigger pull will be identical between different calibers.
RImfire trainer handguns do not duplicate the recoil and the necessary sight picture recovery process. They do duplicate all other aspects of effective combat or sport marksmanship: presentation, initial aiming or pointing, trigger control, reloading and most of the administrative handling. Using the same holster makes sense from the standpoint of economy (only one is needed) and safety. Cheap, floppy nylon holsters often picked for the “unimportant” rimfire pistols aren’t very good for safe re-holstering, but most people buy quality for carry.
Because these conversion kits use fairly wide magazine wells of the larger caliber host frames, and because machining is more cost-effective for small production runs than stamping, the magazines are usually made from billet aluminum and would far outlast any plastic or stamped steel .22 magazine. Durability advantage is definitely on their side. Since the slides also overtravel relative to the minimum necessary distance, the cycle time is relatively slow. That enables the magazine springs to push up taller stacks of ammunition in time for it to feed, leaving to increased capacity. Iver Johnson kit magazines hold 15 rounds rather than 10 or 12 more typical of dedicated rimfire pistols.
With a substantial 1911 frame to support the relatively hefty conversion slide and the thick barrel, it’s not surprising that sub-caliber kits produce good accuracy. They do not require a transfer through an FFL, so you can mail order a kit and have it in hand in a couple of days — or pick one up at your local gun store.