Gentlemen:
I had one of these Baikals for a while.
Now, before your collective eyebrows go up too high, let me explain:
Firstly, it was far-and-away the nicest example I had ever seen! Do a Google-Images search world-wide and see if you can find one that even comes close to this:

Secondly, I wanted to check them out for myself, and the easiest way was to acquire one. Unfortunately I sold it on when I needed the funds for more interesting vintage British hardware, but not without regret.
The examples sold in Australia (well, mine at least!) had "MR-221 Remington" etched on the action-bar, but the name was obliterated by crude scroll engraving before it left the factory, and Baikal MP-221 was etched on the underside of the bar.
But here's the important bit: it had the pressure data etched on the side of the left barrel.

Regrettably, I did not photograph this, as there have been endless e-discussions on the topic of Baikal double rifle pressures, and one is forced to conclude that those landed on the eastern side of the pond had no such markings. Nevertheless, it reads:

"Warning Maximum Operating
Pressure 2200BAR or 31900HST"

My limited understanding of such things is that HST is PSI, give or take. Can anyone clarify this?

Thats a pretty serious .45-70 load, significantly above the 'government' factory loading. Although comparable with most commercial Marlin loads, it is still well short of their maximum capability with top handloads.

Also, the barrels on my MP-221 were step tapered right in front of the chambers, making rechambering to a longer cartridge rather inadvisable.

Hope this is of some interest.