That appears to be a barrel stubbed to an existing SB2 frame... much depends on what it began life as. I actually made two Handi rifle SB2 9.3X74R rifles over the years, one was a Standard model .35 Rem that I rebored and chambered and the other was a Buffalo Classic that started as a .45/70 and I stubbed to 9.3X74... in both cases the extractor functioned, the first as an original extractor/channel, the second had to be cut into the newly stubbed barrel. Your extractor woes are not a tough fix for most machinist/smiths... but you may have another issue, which your difficulty opening the rifle is a tip off to... namely a possible bent hinge pin... ask me how I know that a stiff load from the 9.3 is too much for the SB2 frame/hinge pin... (lol). My first 9.3X74R (the former .35 Rem), blew out two hinge pins before I figured out the loading, necessitating sleeving the receiver and building a new pin, which is a tricky operation to get the rifle to close and latch properly at the end of the job, usually requiring some finesse in both grinding/sanding and/or shimming. If your hinge pin is bent and the rifle is difficult to open, the release button will be tight with no play or wiggle and will usually resist being depressed, whereas there is normally a little play in the button... if this is the case, visually inspect the hinge pin and the hinge pin holes in the receiver to see if the pin is concentric and the holes are tight with no gaps and there is no play in the hinge due to a blown out receiver... then you can smoke the latch and shelf to check for proper (but not excessive) engagement. Lets start there and we can delve further once you check it over.