I’m not sure that (expansion) is the problem either. I wouldn’t buy Tula or Wolf ammo for an AR-15 or an AK because I’ve had problems with the 45 ACP ball ammo on at least one of my 6 1911s. The 1911 in particular is a tight tolerance gun, and when it is loaded with Wolf Steel Cased 45 ACP it ALWAYS jams, every time. The casing gets jammed during extraction lodging down in the throat and the feed area.
I finally determined that Wolf has a thinner extraction rim on the casing that a typical round made of brass. The extractor can start to extract the casing but doesn’t old it securely until it can hit the ejector. Essentially, when the casing can ‘drop down’ it does. Possibly the same problem in .223
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.
I don’t use Russian stuff, I just reload using a 223 Lee precession press and can save my old brass, which bring the cost down to about a third the price of new brass. I buy 62gn M855 pulldowns projectiles, 25 gn of Ramshot TAC powder and #41 CCI rifle primers. Cost about 12 cents a round if I use my old Lake City or Rem brass. Cheapest I have found new 23 ammo in about 38 cents per round, maybe 37 cents if I’m lucky if I buy in bulk. Plus I’m a range rat and can always find brass laying on the ground too.