A rarely seen open bolt semi auto in the USA is the Rubi Extra model 63 and 65 .22 rifles made by Establecimientos Venturini SA in Argentina. The company was apparently operated by a man of Italian ancestry named Guerrino Venturini. They seem to be fairly common in Canada, New Zealand and of course Argentina. They were made with several barrel lengths, and with wood or plastic stocks. The Venturini firm was around in the 1960's and 1970's, but apparently went out of business in the early 1980's. They are described as a copy of the Gevarm rifles, made as a plinker .22 semi-auto, using a detachable magazine.
Here are pictures of a very rusty and abused Venturini rifle.
Here are three pictures of a wooden case supplied with some models of this rifle. The auction apparently included a manual, seen in one picture.
Here is a picture of a plastic stock carbine model, for sale in a Buenos Aires gun shop.
Here is a picture of a collapsing stock carbine model.
Below is a period ad for the Venturini firm's offerings. The open bolt rifle and carbine are the top two guns in the left hand column.
In this ad the open bolt semi-auto .22s are the third and fourth guns on the left hand side. As can be seen they also made air guns, handguns, and shotguns ("Escopeta").
Above is a rough looking long barreled Rubi Extra.
As requested, I deleted the last two photos of another Rubi Extra rifle.