Marek MSG 3J

Thank you to Zach Kessler for providing valuable information for this page


In the mid-1930s a Czech engineer, Jan Ivo Marek, developed an interesting concept for a burst-fire, .45-caliber submachine gun with a high-capacity magazine. No details are currently known as to how this project came about, or when the first prototype was conceived. However it is known that his second prototype, known as the 2J, was demonstrated in 1937 before the Ministère de la Guerre in Paris and trialed against an experimental submachine gun by the Châtellerault arsenal (possibly the Type E.T.V.S.). Marek's 2J submachine gun was still in the developmental stages when World War II broke out, and Marek fled Czechoslovakia for Britain where he continued to work on the design. The third, and probably final, version of his submachine gun was called the "MSG 3J" ("MSG" standing for "Marek Submachine Gun") and blueprints for this gun were drawn up by Marek whilst he was living in London in 1942.

The MSG 3J had many unusual traits. The action was a straight-blowback type housed in a tubular receiver with a spring-loaded firing pin and a reciprocating cocking handle placed on the right. However running along the underside of the receiver was an 11-position fire selector, with settings for full-auto, single-fire, safety, and a considerable variety of burst-fire modes: 2, 3, 5, 6, 12, 16, 25, or 32-round bursts. Marek claimed this that this fire selector was made up of only three components.
The gun was proposed to feed from a proprietary high-capacity "spiral rotor track" magazine of 260 or 156 rounds, with an ammo indicator that displayed red whilst the magazine was loaded and white when the mag was depleted. No details explaining how this magazine operated were provided by Marek. Additionally, a spare 26-round box magazine was to be provided, which would be stored within a recess in the stock. The stock itself was to be constructed from welded steel stampings, as was the pistol grip. The grip had no trigger guard. Forward of the magazine was a folding foregrip which could be extended vertically to act as an "emergency bipod". A muzzle compensator, labelled by Marek as a "Cutts compensator" but in no way actually resembling one, was fitted to the end of the barrel. The sights were basic, consisting of a flip-up rear notch sight and a fixed blade front sight.

The MSG 3J was proposed in three different types: a single-barreled model firing at 786rpm (Type S), a double-barreled model firing at 1,572rpm (Type D), and a triple-barreled model firing at 2,358rpm (Type T). These models were also offered in long and short versions. As far as is known, none were actually constructed, and indeed there is no record of the gun having been tested by the Board of Ordnance in London. Marek continued to live in Britain until his death in 1960.

Below are the blueprints of the Marek MSG 3J submachine gun, sent to me by Zach Kessler.
(Click to enlarge)

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