This is What Led to the Development of Revolvers that Fire Rimless, Semi-Auto Cartridges

A small group of revolver enthusiasts enjoy shooting revolvers chambered for semi-automatic pistol cartridges. Some people also want to carry a small revolver chambered for their primary carry gun cartridge, such as a LCR in 9mm. The history of revolvers and semi-auto cartridges goes back to World War One, and runs parallel to developments in semi-auto pistol technology.

WWI Handgun Shortage

During World War One, the British and the Americans both dealt with a shortage of handguns. The British issued the Webley MK VI, a large frame double-action revolver chambered in the rimmed 455 Webley. At the outset of the war, they placed an order for 20,000 revolvers, which still wasn't fulfilled by 1917. The Americans of course used the M1911 pistol chambered in 45 ACP.

America's Solution

Like the Brits, the USA didn't have enough pistols. They solved this problem with the creation of the M1917 revolver, which entered service when the USA entered the war the same year. The M1917 was actually made by two different companies. Colt and Smith & Wesson both had versions of the revolver, but they shared one critical feature. Both guns were chambered in 45 ACP to make use of the existing stock of ammo. Because semi-automatic pistol rounds lack a rim like revolver rounds, the engineers created half moon clips, which held three rounds by the extractor groove. This headspaced the rounds properly for reliable ignition, and also allowed them to be extracted without modifying the design of the revolver. The S&W M1917 used their existing .44 Hand Ejector design, and the Colt revolver was based on the Colt New Service.

Post-War Popularity 

The M1917 was a commercial success after the war. Surplus guns were common, and S&W produced commercial versions as well. In 1937, the Brazilian government ordered a contract of M1917 revolvers from S&W, some of those made their way back to the States on the surplus market as well. The 45 ACP revolvers were popular enough that the 45 Auto Rim cartridge was invented to remove the need for moonclips. The 1917 was discontinued in 1950, and replaced with the Model 22, which was eventually replaced with the 625 that remains in Smith & Wesson's catalog today.

The S&W 625

Sharing Ammo

When the Wondernine Era kicked off in the 1980s, both Ruger and S&W saw a demand for medium frame revolvers chambered in 9mm. As more agencies switched to 9mm, people who recognized the utility of a revolver wanted guns chambered in 9mm. Ostensibly, this was to share ammo with their primary carry or duty gun. The desire for 9mm revolvers was answered with two different approaches from Ruger and S&W. Ruger kept it simple, and introduced a version of the Speed-Six medium frame revolver with a three-inch barrel, fixed sights, and chambered for 9mm. The Speed-Six required some time of moonclip to work.

Engineering Witchcraft

Smith & Wesson went a different route to solve the problem of revolvers and semi-auto cartridges, creating the fantastic and expensive 547. The 547 was the first revolver to fire a semi-auto pistol with no need for moonclips. Originally designed for the Israeli government, however they backed out of the contract after the first shipment was delivered. Externally, the 547 is a K-frame with a three-inch barrel and fixed sights, but inside the cylinder was engineering witchcraft. Solving the problem of rimless cartridge extraction involved inventing a new extractor, which uses spring-loaded tabs that move into the extractor groove and grab the rounds when the ejector rod is pressed. The 547 was mechanically complex, and rumor has it that it was the most expensive to manufacturer revolver that S&W ever made. It died in 1985.

Of Course, There Was a 10mm

In the early 90s, S&W flirted with 10mm in a revolver. The 610 was offered to capitalize off the popularity of the FBI's new darling, and since it used the same diameter bullet as the old 38-40 Winchester, it wasn't hard to scale the existing N-frame design for it. Unfortunately, the 610 hit at the same time the FBI was falling out of love with the 10mm. That might have been the end of the weird love affair between revolvers and semi-auto cartridges if it wasn't for one thing.

Competition Shooting

S&W 929 9mm

The savior of this crazy idea was competitive shooting. During the late '90s to early 2000s, the action shooting sports of IDPA (International Defensive Pistol Association) and USPSA (United States Practical Shooting Association) were booming. Both sports had divisions dedicated to revolvers, and the rules of both games favored competitors shooting 45 ACP revolvers loading with moonclips. The S&W 625 was the de facto choice for gun games for some time. Smith & Wesson also reintroduced the 610 on again and off again for the devoted 10mm fans. Perhaps the most fascinating gun they made during this time was the Performance Center 646, a semi-custom L-frame with a titanium cylinder chambered in 40 S&W. They built 900 of these guns, and it's one of the few guns I deeply regret selling. Before 2014, USPSA changed their rules allowing 8 shot revolvers to compete in revolver division. This opened the door for a new group of 9mm revolvers, starting with the enormous N-frame 929 from Smith & Wesson. In 2020, Ruger's Custom Shop produced their first 8-shot 9mm, the equally enormous Super GP100.

S&W 929 Miculek 9mm $999.97 Cabelas.com

Concealed Carry

While competition shooting was chugging along, the concealed carry revolution was happening. Over the course of the 2000s, the landscape of concealed carry in the USA changed so that as of this writing all 50 states have some mechanism of legal concealed carry. With 19 million carry permits in the United States, and 9mm by far the most popular round for LE and concealed carry, people wanted small revolvers for concealed carry that shared a caliber with their “main” gun. Smith & Wesson led the way with the 940 Centennial, a shrouded hammer J-frame chambered in 9mm. Ruger answered with a 2-inch model of the SP101. Both guns required moonclips to function. S&W discontinued the 940 in 1998 due to slow sales, while Ruger still offers the 9mm SP101. In 2014, Ruger announced the LCR in 9mm, which is probably the best choice for people who want their backup gun to share ammo with their main gun.

Ruger LCR 9mm $599.99 Cabelas.com

Today all the major revolver companies produce guns chambered for some form of semi-auto pistol cartridge. Ruger has small guns for concealed carry and big competition revolvers, while Smith & Wesson has focused on competition and target shooting guns. Charter Arms has carry guns in 9mm, 40 S&W, and 45 ACP; Chiappa offers the Rhino in 9mm and 40 S&W; and even Taurus is in the game with small, defensive oriented revolvers chambered in 9mm and 380 ACP. It's safe to say that this fad started in 1917 isn't going away any time soon.