Refining the Thompson to M4 Magazine Adapter

Hello everyone!

It's been a while since I have made a post here. A lot has happened in my life, but that is not the point of this post. I am posting to provide images and information on an update to one of my best airsoft accessory designs. A few years ago, I bought a boneyard airsoft Thompson AEG.  It did not have a magazine included with it, but I managed to find and buy a stick magazine at my local store (Airsoft Barracks). I used this magazine to take measurements for an accessory that is both ridiculous and highly practical. It would never work for a real firearm due to the differences in which type of ammunition the firearms take. Since airsoft uses pretty much exclusively 6mm plastic balls, this accessory becomes valuable and practical. It is a magazine adapter that allows Thompsons to use M4 magazines.

The adapter slots in like a factory Thompson magazine, but it has an opening on the bottom to accept most M4 magazines. The left side of the adapter has a secondary magazine release that allows you to easily swap between M4 magazines. To go back to using Thompson magazines, simply pull on the Thompson's built-in magazine release and slide out the adapter. These adapters will allow anyone to use the most standard and easy to find/borrow magazines on any airsoft field. The vast capacities of M4 drum magazines are now within reach for those of us who want to use the Thompson in our battles.

    Here is the adapter with a Firestorm Drum Magazine installed.

    Here is the adapter with a shorter M4 Magazine installed.

    Here is a close up of the logo that is on the side of the magazine adapter.

The design has undergone some changes through the years.  At first, it was designed to be printed in two pieces (the main body and the magazine catch). This worked for a time, but prolonged use in combat would lead to the internal feed lips breaking off of the adapter. I fixed this by removing the feed lips and replacing them with a cutoff section of a pen tube. This is much sturdier and more reliable. I have also refined the magazine release to better interface with the magazines. Additionally, I altered the adapter's geometry to look cleaner. The adapter was also originally designed to use the spring of a Pilot G2 pen. This worked for small batches, but the cost of the pens quickly added up. I have adjusted the design to use a less expensive pen that can be bought in greater quantities. 

The adapter works well and feeds properly. The only downside to this adapter is the fact that some BBs will spill out when the magazine is removed unless the gun is inverted when removing the magazine. The long feed tube in the adapter means that more BBs will be wasted when changing magazines.

I am selling these adapters for $30 + shipping (made to order). To place an order, please reach out to me at artemasairsoftarms@gmail.com.

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