Building the World’s Smallest 10mm Pistol

Screen Shot 2015-08-11 at 8.54.45 AMThey say dynamite comes in small packages; well, they’ve never seen this gun.

I’ve been enjoying the revival of the 10 mm semi-automatic pistol cartridge this year just as much as the longtime fans who have been saying, “See, I told you so!” since 1983. Despite its up and down ride on the outdoor media’s popularity rollercoaster, this potent rimless .41-cal. round has maintained a loyal following. I’ve always liked magnum-power pistols, so even though I am a relatively new convert to the 10 mm it fits right in with the other hard-hitting handguns that often follow me out to the range.

I’ve worked with various 10 mm pistols, including models that have been slimmed down (STI Nitro) or trimmed (Glock G29) for more comfortable carry. But is it possible to build a truly pocket-sized pistol for this potent .41-cal. cartridge? Thanks to Bond Arms, it is. The company currently provides all of the components for a tough little 3” barrel 10 mm pocket rocket, just a little assembly is required.

My quick and easy at-home conversion used a factory configured Cowboy Defender as the base gun. It ships with a 3″ long .45 Colt/.410 barrel, an updated trigger and hammer, wood grips, and no removable trigger guard (which shaves off a bit of weight). The barrel’s hinge pin twists out of the frame using a hex key while the grip screw can be loosened and removed with a small standard screwdriver. The frame was stripped and ready to become a mini 10 mm in under a minute.

Bond Arms provides polished and matte finish stainless steel accessory barrels ranging from 2.50″ to 4.25″ in length chambered in a variety of revolver, pistol, and rimfire calibers. Tucked in amongst this host of options is a polished 3″ Defender barrel chambered for 10 mm. This is also the shortest 10 mm option the company offers. The accessory barrel fit the Cowboy frame perfectly and operated smoothly. Like the other Bond Arms semi-auto barrels, the 3″ 10 mm version does not have an extractor. Instead, a slot is cut into the right side of the dual chambers so that fired rounds can be lifted out of the barrel with a thumbnail or the rim of an empty cartridge case.

Standard size grip panels provide the smallest grip profile for this platform. But which type of grip material to choose? The old-school smooth hardwood grip panels that came with the Cowboy allow the bird’s head grip frame to roll back in the hand to reduce felt recoil. But modern soft rubber grips provide improved purchase for keeping a hold of the gun as it kicks. Both grip types do the job nicely, so it’s mostly a matter of preference. For this hot potato 10 mm configuration a set of soft rubber grip panels were installed.

When completed, the home-assembled Cowboy Defender 10 mm was 5.5″ long, 1″ wide (across the frame) and 3.7″ tall. The all-stainless steel gun tipped the scale at 19.7 ozs. unloaded. To the best of my knowledge, this is as small as a 10 mm handgun gets.

Because the 10 mm case length is just shy of being 1″ long (0.992), the 3″ barrels provide about 2″ of rifling to stabilize the bullets as they leave the gun, which is not a whole lot to work with. However, the pistol’s chambers are closed with no pressure loss due to the lack of a cylinder gap (revolvers) or moving action (semi-auto). As a result, the pistols produce more bullet velocity than one might expect.

But the whole point of shooting 10 mm is to squeeze as much velocity out of the round as possible. So, I contacted Gordon Bond with a proposal (we’ve been friends for several years now, so he was willing to put up with some gentle, but firm, arm twisting from me). Since the 10 mm is a hot topic this year, why not give fans of the cartridge a new barrel for 2015? In addition to the 3″ version, work up a 4.25″ version as well. That way customers (like me) would be able to choose between compact size or maximized performance.

Read more: americanrifleman.org

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