It’s not expansion. It’s lack of expansion. The steel doesn’t expand and “fill” the chamber like brass does. So, you get dirt and grit in the space around the chamber that builds up with each shot. Eventually, it wedges a round in place. Straight wall cartridges have the worst problems; tapered, the least.
And, the Wolf may well have a thinner rim, which would only exacerbate the problem.
I don’t see why mixing a round of brass wouldn’t work with pistols as well as rifles, though, provided you started with a clean chamber.
My Bersa Thunder 9 (that I borrowed) will feed and extract Wolf/Tula just fine, but occasionally doesn’t have enough power to chamber a new round. Never had a round stuck in it, though.
Don’t know, but I’ve measured the thinness of the Wolf steel extraction rim and it is noticeably thinner. the extractor only works in a direct pull pack mode and doesn’t ‘hold’ it for the ejector.