1 Like
The Winchester Model 1907 was originally designed by Thomas Crossley Johnson as a blowback-operated semi-automatic rifle. However, the mention of Swebilius points to a fascinating, lesser-known chapter in firearms history involving Carl Swebilius, a legendary gun designer for Marlin and later the founder of High Standard. [1, 2]
Swebilius experimented with and patented conversions to alter existing blowback actions into gas-operated systems, specifically looking at Winchester’s self-loading platforms.
The Mechanics of the Conversion
A standard Winchester Model 1907 relies on a massive, heavy counterweight hidden underneath the wooden forend to keep the breech locked until chamber pressures drop to a safe level. This made the gun notoriously front-heavy and prone to cracking its own woodwork over time. [1, 2, 3]
Swebilius’s concept sought to redesign this operation:
-
Gas Port and Tappet: A small hole (port) would be drilled into the barrel to bleed off high-pressure gas after a round was fired. This gas would drive a piston or short-stroke tappet.
-
Lightening the Bolt: By transitioning the rifle to a gas-operated system, the massive, reciprocating blowback counterweight under the forend could be heavily reduced or entirely removed. [1, 2]
-
Smoother Cycling: Gas operation allowed the action to unlock more dynamically based on pressure rather than pure inertia, mitigating the harsh, violent recoil impulse typical of a heavy blowback action. [1]
Connection to the M1 Carbine
While Swebilius toyed with conversions of Winchester’s early self-loading rifles, Winchester’s own engineers eventually followed a very similar line of thinking. During the development of the M1 Carbine, Winchester engineers took the foundational trigger housing design of the Model 1905/1907 and married it to a gas-tappet system. The cartridge itself—.30 Carbine—was even directly adapted from the Winchester .32 Self-Loading round. [1, 2]
If you are researching a specific patent or a rare toolroom prototype marked by Swebilius, please let me know! I can help you look up patent numbers, historical manufacturing timelines, or compare it directly against the more famous Lebman fully-automatic conversions used by 1930s gangsters.
Lebman fully-automatic conversions
1 Like
Marlin UD-42 from the Dutch Resistance - Forgotten Weapons
Jan 11, 2018 · The UD-42 was originally the design of Carl “Gus” Swebilius, who was at the time (1940) working for the High Standard …
The UD M.’42: America’s Clandestine Submachine Gun
Oct 29, 2022 · Swedish-born designer Carl “Gus” Swebilius (l.) was the brainchild behind the UD M.’42, while Col. René Studler (r.) …
1 Like