Analysis of information sources in references of the Wikipedia article "Obturating ring" in English language version.
The mechanism consists of the breech, and an interrupted screw breech block on a hinged mounting. [...] The Welin breech block was invented by Axel Welin in 1889 or 1890.
The mechanism consists of the breech, and an interrupted screw breech block on a hinged mounting. [...] The Welin breech block was invented by Axel Welin in 1889 or 1890.