Hello and welcome back to another edition of The Rimfire Report! In this weekly series, we look at a lot of firearms and technology surrounding the rimfire firearm world, and this week we have an extremely uncommon topic to explore – a rare Fleming 22LR conversion kit. Most of you rimfire junkies will already know of a few common conversion kits out there – most notably for the AR-15 platform. This time we’re taking a look at an extremely rare conversion kit meant for the HK 94 / MP5 platform.

The Rimfire Report: Rare Fleming .22LR HK 94/MP5 Conversion Kit

Fleming Firearms historically has been one of the most prolific producers of HK auto sears dating as far back as the ’80s. The NFA firearms manufacturer is also commonly known for making many reproduction H&K submachine guns as well as full auto sears for FN FAL rifles.

Pictured here is the 22LR barrel insert for the conversion kit – installation is said to be fairly straight forward and simple to do.

Unfortunately, William Fleming was charged on some dubious violations of NFA regulations when conducting normal business operations and since then Fleming has been hard to find out in the open.  Despite the charges being filed against him in 1994, some online forums claim he is still doing a limited amount of business, although in what capacity and the extent he is doing business is unknown to me at this time.

The conversion kit in question was found on the popular gun auction website GunBroker.com and for sale by Chester County Armory. The Fleming 22LR conversion kit is listed as used but in working condition and complete with all the parts needed to convert an HK 94 or MP5 from 9mm to 22LR. The seller specifically notes that this version of the rare fleming 22LR conversion kit will not work on the SP89 or K version of the firearm (although the instructions clearly stay that it is for the SP89).

What’s in the Box?

The biggest departure besides the caliber from the standard design of the MP5 is the inclusion of the special fleming 22LR magazines. Each of the magazines has a 20 round capacity and seems to work quite reliably when using quality ammunition. There are several of these conversion kits in collectors’ hands and most of them seem to work very well in both semi and full-auto builds – I’ve provided a few videos below of the conversion kit in action.

In addition to the magazines, the kit also includes a near-identical copy of the H&K 22LR conversion kit barrel aside from its overall length. On that note, the H&K conversion kits are arguably even rarer than the Fleming kits and rumor has it that out of the 200 manufactured, only 75 were imported into the United States. The kit also includes a recoil spring assembly, 22LR bolt as well as the bolt/recoil spring connecting piece.

The kit typically comes with two 20-round 22LR magazines that are specific to the Fleming conversion kit

Possible Conversion Resurgence?

22LR conversion kits are obviously nothing new and it seems like Fleming has been doing it particularly well since the 80s. In addition to the MP5 conversion kits, Fleming also produced some H&K G3 22LR conversions as well for those lucky enough to own a G3 style rifle. The concept of a conversion kit is especially attractive to me since I try to be pretty lean on the number of firearms I own (although this is a problem that continues to grow despite my best efforts).

Conversion kits allow you to save on space and parts by making use of one firearm for both calibers but the major downside is the downtime you’ll have when swapping out the conversion kits as it’s not a simple “plug and play” process like swapping out an upper receiver. However, despite this, 22LR conversion kits still tend to be popular and perhaps might become even more popular given two specific reasons.

First, the fact that there is a significant ammunition shortage right now as well as an inflation of ammunition prices means that 22LR once again has upgraded its status from a simple plinking round to a legitimate training round because of its affordability – if you’re able to use your duty/carry platform and train with cheaper ammo, now is the time to do it.

Second, now that H&K has come out with the SP5 and the SP5K we might see new demand for these 22LR conversion kits given that there are significantly more MP5s on the market. Although, to be honest, those who can afford an SP5 or SP5K right now probably can also afford the current exorbitant prices on 9mm ammunition.

Still up for grabs

As of writing, the auction for this rare Fleming 22LR conversion kit is still active and has 4 days remaining on it. The auction currently has no bids and has a starting bid of $2000 with no reserve. If you’re interested in bidding on the auction you can check out my brief guide to using GunBroker.com here. On the other hand, for about 1/10th the price you can pick up a GSG5. In any case, thanks for stopping by to read The Rimfire Report and we’ll see you all next time!