What Happened to the Toggle Action?

The Luger pistol became a worldwide celebrity among firearms during World War I. If not the most recognizable handgun in the world for over a century, it is certainly the most recognized auto-loading pistol. I’m sure its appearances in the Call Of Duty video game have helped to sustain its fame among millennial-generation shooters and non-shooters alike, most of whom have never seen one in the real world, much less shot one. Though the Luger owes most of its fame to two world wars and gamers, I’d argue that fame is warranted by the pistol’s engineering alone.

Biological Engineering

Anyone with a basic understanding of firearms knows the Luger is an odd bird. It was, and remains, the best application of the toggle action to a handgun, specifically a toggle, locked-breech short-recoil operated action.

The toggle action might be best explained by comparing it to how the elbow joint in your arm supports your body weight when doing a push-up. The elbow joint connects the upper and lower arm bones. Removing the 10% or so of people with hyper-flexible joints from consideration, a normal elbow allows movement through most of a 180º arc. It’s easy to hold up your body weight at the apex of a push-up when your elbow joint is fully extended 180º to orient your upper and lower arm bones in a straight line because your upper and lower arms are locked, bone against bone, at the elbow. The push-up gets hard the moment you start to lower yourself by bending the elbow joint. Bending the elbow unlocks the joint and your muscles must take over the work of supporting your body weight.

The toggle locking principle, as applied to the Luger, is oriented horizontally with a sliding breechblock at the front connected by a pivot pin joint to one end of a two-part toggle link with the elbow facing upward. The other (rear) end of the toggle link is attached to a pivot pin at the rear of the pistol’s barrel extension/upper receiver assembly. Spring pressure is constantly holding the toggle elbow straight in the locked position.

When the pistol is fired, the toggle initially stays straight and locked. This focuses the recoil energy into moving the whole mass of the barrel, upper receiver and toggle mechanism rearward on the lower frame, about 1/8″ while the bullet leaves the barrel and chamber pressure drops to a safe level. At this point, the upper receiver assembly is about halfway through its course of rearward motion.

Further travel puts the Luger’s distinctive circular bosses that protrude from each side of the rear toggle link in contact with slopes machined on each side of the lower frame that cam the toggle open. The toggle is fully unlocked before the upper receiver assembly stops recoiling. Remaining recoil energy is then focused on cycling the toggle link itself, which draws back the breechblock to extract the fired case. Spring pressure then reverses the cycle, drawing the toggle closed to strip a fresh round off the magazine, loading it in the chamber, locking, and then pushing the whole upper receiver assembly fully forward into firing position.

Toggle Ancestry

Though the Luger was the most successful toggle action-locked short recoil pistol operating system ever made, it was not the first. That credit goes to Hugo Borchardt’s C-93 semi-automatic pistol. Offered to the public in 1893, it was one of the very first autoloading pistols in production. Beautifully built but preposterously awkward to use, only about 3,000 were made. Austrian engineer Georg Luger corrected the shortcomings of the C-93, which resulted in several new patents and the pistol and the 9 x 19mm cartridge (9mm Luger) that still bear his name. About 3 million Luger pistols were made during the roughly 50 years the pistol saw service around the world. The first Luger pistol to go into production was the Model 1900 adopted by the Swiss military. It remained their standard sidearm until 1949.

You could say that George Luger’s Luger, which was actually the world’s second toggle-locked short recoil action autoloading pistol, was a home run hit for this type of operating system in handguns. Curiously, beyond prototypes, this operating system hasn’t been used again in handguns to this day. I say this purposely excluding the unlocked, simple blowback, toggle-operated actions that were used by Erma and Stoeger in their post-war Luger-style semi-auto pistols, most of which were .22LR.

Ammo Limitations

I suspect the main reason we haven’t seen toggle-locking action pistols since the Luger is because, as a purely mechanical system, the toggle is rather particular about who it works with and must be engineered to match a specific cartridge. In a military application, where the cartridge is standardized, this isn’t a problem. Military specifications defining bullet weight, powder, charge weight, brass dimensions, etc., ensure predictable function.

However, the civilian market would never accept being limited to one type of ammunition, and shooting ammunition the action wasn’t engineered for is a formula for frustration. In test firing my excellent condition, veteran bring-back, 1915 DWM Luger for this story,

I had failures to feed almost 30% of the time with commercial ammo. In a gas-operated toggle locking action,it is possible to tune the action to the load to some degree. John Browning patented a gas-operated toggle-locking action pistol in 1897, but it was never produced.

Other Toggle Applications

By far, the most significant application of the toggle lock to firearms was its successful adaptation to automatic weapons by American-born inventor Hiram S. Maxim in the 1880s. Maxim machine guns were sold worldwide, and their reliability and prodigious rate of fire made late 19th-century military ground combat tactics obsolete. Though big and heavy, these weapons can still be found at war today. Ukrainians are using World War II vintage Russian-built Maxim, water-cooled, heavy machine guns to shoot down Russian drones. Unique to Switzerland but still worth mentioning is their toggle action 7.5x51mm Leichtes Maschinengewehr Modell 1925, a domestic design developed by Swiss Army Colonel Rudolf Furrer. It was adopted in 1925 and stayed in service into the late 1950s.

Manually locked toggle actions were most famously used in American lever-action repeating firearms, beginning with the Volcanic pistols and rifles in the mid-1850s, progressing to the Henry Rifle in 1860, and perfected in the Winchester’s 1866 and 1873 rifles. With the exception of the Volcanic guns, modern reproductions of all these toggle-lock lever actions are still in production.

With the exception of the Walther Automatic Shotgun, a semi-automatic toggle action produced from 1921 to 1930 in fairly small numbers, semi-auto toggle action long guns never attracted sufficient military or civilian interest to warrant production. Among the most notable ideas that floundered were rather advanced guns from John Petersen, Karl Heinemann and even George Luger himself!

On a visceral level, I speculate that semi-auto toggle action centerfire long guns may have just offended human sensitivities about personal space with their violent, exposed operation. John Browning’s popular lever action repeaters (Model 1887, 1893 and 1897 shotguns and 1894 and 1895 rifles) all exposed their metal private parts while cycling, but they projected them downward, below the line of sight. By contrast, most toggle actions threw their junk right up in front of your face. Nobody likes that.

One place where the toggle action resurfaced long after its heyday was in the world of rimfire competition rifles. Russian Izhmash manually operated toggle action .22LR rifles were used in Olympic biathlon competitions by Soviet athletes going back to the 1980s and are still in production. Just this year, Hamerli Arms introduced the Force B, .22LR/.22WRM switch barrel sporting rifle, with a similar side cycling, manual locking toggle action. It is delightfully easy and fast to shoot and can be cycled with just one finger.

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