A couple of weeks ago, we published an article telling about the release of the Standard Manufacturing G4S rimfire rifle. Despite its modern look, the design elements of this rifle indicate that it is likely based on the Standard Manufacturing 1922, a scaled-down semi-auto rimfire replica of the Thompson submachine gun. This started a discussion about Thompson SMG replicas in the comments section of that article and one of our readers, Mike Johnson, posted the above-embedded picture and commented: “I wanted a Tommy gun in .22lr, so I made my own. This is what Thompson or Standard Manufacturing should have made. It uses 10/22 fire control and magazines“. It looked really interesting and intriguing both to this author and many TFB readers, so I asked Mike to share more details and pictures of the project and to give permission of using the information for writing an article about his rimfire Tommy gun. Mike kindly agreed, and today we’ll see how exactly he designed and built this hot gat.

Everything started with a combination of parts Mike had at hand which he thought were perfect for using in a rimfire Thompson submachine gun replica project. Particularly, he had a real Thompson SMG stock that he had bought at a gun show ten years ago, and a number of Ruger 10/22 parts (bolt, fire control group, a variety of magazines) sitting in his spare parts box.

3D rendering of Mike Johnson’s rimfire Tommy gun.

With the decision of using the mentioned parts made, Mike started designing the rest of his rimfire Tommy gun around them. The newly designed parts include the upper and lower receivers, pistol grip and forend, trigger, muzzle device, rear sight protector, etc. Most of these parts are machined out of solid blocks of material on a Haas Mini Mill. One exception is the rear sight protector which is made by cutting a piece of square steel tube. The rear sight itself is a Williams peep sight.

The lower receiver machining process.

The machining of the upper receiver.

The trigger.

The pistol grip was machined, too.

The 10/22 trigger mechanism parts and the new trigger are held together in the original 10/22 trigger guard assembly housing, however, Mike cut the actual trigger guard off as the lower receiver he machined has an integrated trigger guard. This modification made a fire control group sub-assembly out of the 10/22 trigger guard assembly which is inserted into the lower receiver of Mike’s Tommy gun.

The rear sight assembly and compensator.

The Cutts-pattern compensator is pinned and welded to the barrel to have an overall barrel length of 16.1″ required by the legal definition of a rifle. The original Tommy gun barrel with Cutts compensator is about 12″ long. Usually, increasing the barrel length of a replica firearm to meet the law requirements makes it look odd in comparison to the original gun. However, as you can see, despite having a 4″ longer barrel, Mike’s gun doesn’t look to have wrong proportions. How is that possible? Well, the trick is in creating a sort of optical illusion by having a longer forearm thus keeping the barrel-to-forearm length ratio similar to that of the original Thompson SMG. That’s a pretty cool solution!

Mike’s rimfire Tommy gun assembled, unfinished.

Mike’s Tommy gun replica looks really nice with the drum magazine. As you can see in the picture above, the curved 10/22 magazine doesn’t look as good because real Thompson submachine gun box magazines are straight. It must be really hard to make a high-capacity reliable .22LR magazine without that curve due to the design of the rimmed cartridge. A fake straight magazine body attached to the 10-round 10/22 mags could be a solution should one want to have a magazine that looks like a Thompson SMG box magazine.

Mike named his gun Johnson Semi-Automatic Carbine.

This is a really cool project, isn’t it? Although a lot of borrowed parts are used, it is still quite a complicated and advanced project requiring a lot of designing and manufacturing skills to accomplish. Of course, it’s not a 100% accurate replica in all small details but it looks really good for the amount of 10/22 parts used. This gun should also have quite a bit of customization potential with aftermarket 10/22 parts such as bolts and trigger mechanism components. I think Mike’s method of creating a replica gun with such extensive use of Ruger 10/22 parts could be applied to making rimfire replicas of many other historical firearms that are otherwise hard to acquire due to rarity and prohibitive price.

I think someone should purchase the rights and start manufacturing this gun. All the R&D work is already done and only minor tweaking may be needed to produce it. That said, this could probably end up being a relatively affordable gun!? Tell us in the comments section what price point do you think would be justified for a gun like this. Replicas of what other firearms do you think could be created using 10/22 parts?

Many thanks to Mike Johnson for sharing the pictures and story of this project!