When I filmed this, I had limited time and figured I would do the shooting first and then film the history and disassembly of the gun afterwards. Alas, I ran out of time and never did get that part completed. I will follow up with a video on the history of the Sjogren the next time I have access to one, but I think the shooting footage worth posting by itself. Also, please note that I did not have my proper high speed camera on this trip (I had not anticipated being able to shoot anything!) and so we used an iPhone slow motion function instead. Happily, the Sjogren operates slowly enough for that substitution to still work decently.
Anyway, the Sjogren is a very unusual system, an internally-locked semiauto shotgun developed by a Swedish inventor and produced in Copenhagen. A rifle variation of the system was tested by a few militaries but never put into production. A few thousand of the shotguns were made and sold commercially prior to World War One. You can find more information on them in my full article.
As I say in the video, I found the Sjogren to be a quite pleasant shotgun to shoot, especially for being chambered for 12ga shells. I had a Walther toggle-locked shotgun out at the range the same day, and the contrast between the two was quite significant!