From an 1873 lever-gun round to a 2022 carry cartridge: what these uncommon calibers are, and why each one stayed uncommon.

Every gun counter has a top shelf of calibers it sells by the case and a bottom shelf of everything else. The bottom shelf is where this series lives — handgun cartridges with real histories and real firearms still chambered for them, that simply never sold in mainstream volume.

Sorting them by why they stayed small is more useful than sorting by bore diameter. The same list contains frontier-era rounds, Victorian pocket-revolver rounds, the first successful autoloader cartridges, and two designs younger than most smartphones.

Frontier and service rounds

The oldest name here is 44 40 winchester cartridge: Winchester introduced it in 1873 for the Model 1873 rifle, and Colt chambered the Single Action Army for it five years later so a rider could carry one box for both guns. 38 long colt ammo armed the U.S. Army from 1892 until complaints from the Philippine campaign pushed the service back toward .45-caliber sidearms. Across the Atlantic, 455 webley ammo was the British service round from 1891 through the Webley Mk VI of the First World War.

The pocket-revolver decades

32 smith and wesson long ammo is the polite, low-recoil round Smith & Wesson introduced in 1896 for its first swing-out-cylinder revolver, and it went on to arm police departments — New York's among them — for decades. It is the direct parent of the .32 Magnum family covered later in this series.

The autoloader arrives

7.63x25 is the round the Mauser C96 “Broomhandle” was built around in 1896, a bottlenecked cartridge that briefly counted as the fastest production pistol round in the world. It set the template the Luger's 7.65 mm round would follow two years later.

Modern attempts at an old problem

327 federal mag arrived in 2008 as a lengthened .32 H&R Magnum, designed with Ruger so a small-frame revolver could carry six rounds where a .357 cylinder holds five. 30 super carry is newer still — Federal launched it in 2022 as a slimmer-than-9mm carry cartridge meant to add magazine capacity without giving up much on the target.

The specialists

Three rounds here were built for one narrow purpose. 22 jet ammo necked a .357 Magnum case down to .22 caliber in 1961 for the Smith & Wesson Model 53, chasing rifle-like velocity from a revolver. 41 mag ammo was Remington and Smith & Wesson's 1964 pitch for a police cartridge between .38 Special and .44 Magnum — departments mostly said no, and hunters said yes. 4.6x30 is Heckler & Koch's cartridge for the MP7 personal defense weapon, engineered to defeat soft body armor at close range, not to fill a sporting niche at all.

What this tells a buyer

None of these cartridges failed. Each was overtaken by a better-marketed rival, tied to a platform that stayed uncommon, or built for a problem only a few shooters ever had. Knowing which of those three stories applies to a given round is the first step toward deciding whether to build around it.

Availability, pricing and shipping requirements for any cartridge listed above can change and vary by state. Confirm current stock, your state's age and identification requirements, and any local shipping restrictions before placing an order.