Self-proclaimed HK USP fanboy LifeSizePotato takes us on a video tour of his 10mm USP conversion. LifeSizePotato has an epic YouTube channel with some rather rare handguns that make me drool every time he releases a new video. I would sell a kidney to get a chance to go through his collection and fondle all the ultra cool pistols.

This video, he shows us his latest project gun, a Heckler Koch USP .40 S&W that he has converted to fire 10mm. Apparently, this is a conversion that has been floating around the gun world for some time that seems to have eluded me. As a USP fanboy I am nothing short of disappointed in myself for overlooking this mod. Hell, I even had a police trade-in USP .40 a while back that I picked up for a song and sold promptly because I came to my senses and decided adding another caliber to my collection was stupid.

LifeSizePotato says he used a modified STI magazine, an 18 pound recoil spring, and an EFK Fire Dragon barrel reamed out to 10mm by a gunsmith to create the German 10mm powerhouse. Since HK never produced a USP in this caliber it is super cool to see a fan of the platform build something that probably should have been built to begin with.

If you haven’t checked out his YouTube channel, it has some outstanding content. You should probably block off a hour or two to spend drooling over his collection.