The Baikal .30-06 double rifle is made from same action they use for their Baikal sxs 20 gauge shotgun, and they state that fact on their website. I have machined these actions enough to know that they are some sort of alloy steel of very high quality, maybe 4140 or similar---fact is, they have to be, to hold up under pressures of .30-06, high for a double rifle, while using only Purdey double underbolts with no third fastener at all. My viewpoint is that the Russians used very fine steels, but didn't take enough time for details, nicely finishing, and fine tuning. Since they hold up to .30-06 pressures, they will certainly hold up to any other cartridge producing less pressure. Pay more attention to barrel strength, for any barrels you may put on such actions, than to strength of action itself, because the action will certainly hold up for anything with same or less pressure (rearward thrust against action, over AREA of cartridge head) than .30-06. That area of head will vary, of course, with different size cartridge heads, different calibers, so it should be calculated, as explained in W. Ellis Brown's books, converting double shotguns to double rifles.