With a loaded weight going well over 13 pounds, this 1950s battle rifle was the go-to arm of the Swiss Army for decades and is a much sought after collectible here in the states.
Why was it designed?
The Swiss Army had a long history or innovative rifles including the tubular magazine Vetterli that was soon used all over Europe, the excellent Schmidt Rubin series guns that held the line in the Alps in World War I, and the K.31 rifles which equipped the country’s 500,000-citizen army in World War II.
The thing is, those straight-pull bolt action K.31s were by the 1950s becoming increasingly obsolete, as the armies of Europe were adopting semi-auto and select-fire battle rifles and assault rifles such as the NATO FN FAL, HK G3, and M-14 and the Warsaw Pact’s SKS and AK-47 series guns. Behind the evolutionary 8-ball for the first time in a long time, the Swiss went looking for the mother of all battle rifles and Schweizerische Industrie-Gesellschaft Waffen-Department (SIG) had just what they were looking for.
Run up to the 510
SIG’s Rudolf Amsler came from a long line of firearms engineers. His grandfather had in the 19th century helped redesign Switzerland’s 1842 percussion muskets into the M59-67 Milbank Amsler breechloader while the younger Amsler held a number of international firearms patents around the globe. In 1955 he came up with a select-fire rifle that left other tried but rejected SIG semi-auto designs (the SK46 and AK53) behind.
The very heavy, part LMG, part rifle, prototype AM55 Photo credit
Amsler’s AM55 rifle, which borrowed the same roller delayed-blowback system of the very successful German MG42 machine gun of WWII and Mauser’s Stg.45(M) assault rifle, but was chambered in the same standard 7.5×55 mm GP11 round used by the K.31 and Schmidt Rubin series bolt-action rifles. Its distinctive T” shaped cocking handle is very familiar to users of those guns.
The long action and full-sized round produced a rifle that was 43-inches long with a 23-inch barrel, which is almost a dead ringer in length to the FAL and M14, though a bit longer than the SKS and AK. However, unlike the SKS, Amsler’s AM55 rifle allowed for full-auto fire at the flick of a switch allowed the gun to be used as a relatively effective light machine gun. Of course, the 500 rounds per minute cyclic rate meant the 24-round curved detachable magazine would be drained in about three seconds of sustained fire, but it was still some serious volume for that brief time period– and could be used by every rifleman equipped with one such gun.
While the select-fire U.S. M14 had complaints of running away when on full-auto, the heavier Swiss gun, with a built in bipod in the forearm, vented metal handguard, a pistol grip and a recoil buffer in the oddly shaped buttstock, was much more controllable. Further, the Swiss Army tactics of being able to lay in ambush for invaders coming up winding mountain roads made the ability to have their soldiers chose between accurate single-shots out to the 174-grain 7.5mm’s effective range of 800-yards, and the ability to set a platoon of these rifles to full auto for an ambush, was ideal.
When tested by the Army, they liked Amsler’s SIG AM55, but asked for some changes to the 15-pound gun, including ditching its wood furniture for plastic, which saved some weight, and a modified folding trigger that allowed for use with mittens. The result was the 12.25-pound (unloaded) SIG 510, which was adopted in 1957 as the Sturmgewehr 57 (Stg 57).
And, while homely, it proved utterly reliable and is still in some military service today– as well as being the subject of intensive search by U.S. collectors…
Read the rest in my article at Firearms Talk