007 eat your heart out because there’s a new king of concealable lethal gadgets on the scene. When it comes to homemade guns, for me, this one takes the cake and eats it too. The marker sized hand cannon dubbed the “Pen Gun” by its owner Josh Geho is just one of many of his other impressive amateur gunsmithing projects.

I made the gun from a leftover scrap barrel segment of an FN PS90, a $13 bar of 4140PH steel. I used and AR-15 firing pin as the iginition source for the round. The total cost of the build minus the tax stamp was about $20.

Quite an impressive build for just $20. The Pen Gun falls into the category of an AOW or “Any Other Weapon.” 

Josh told me that he had quite an interesting story when dealing with everyone’s favorite government agency.

Government competency at its finest

When I filed the Form 1 for my pen gun, I only paid $5 for the stamp, assuming that was the cost to make an AOW. The ATF approved it, and sent me the $5 red stamp (above). Months later, I got a certified letter demanding an additional $195 to pay the correct denomination, plus the original form returned, or else I had to destroy the pen gun.

Being crafted from the barrel of a scrapped FN P90S, the gun fires the 5.7×28mm cartridge used in both the FN P90 and its companion handgun the FN Five-seveN. As small as the cartridge is, it packs quite a punch, especially in such a small frame. Josh had this to say about firing his Pen Gun for the first time.

This little guy has the most recoil of anything I ever shot. All the recoil is transferred to an area 0.74 square inches. The first prototype cut a circle in my hand. I also had a friend of mine who fractured a bone in his palm from one shot (his scaphoid, to be exact).

Be careful out there folks!