I picked up 5 unopened cans of Norma 205 for little of nothing. How close is it to MRP or R22?

I'm not sure that Norma even markets this powder any more. That said, 205 is closer to RL19 or N160 than it is to RL22/MRP.

N-205 was replaced with MRP many years ago. They should be approx. same.

TSJ; good find, haven't seen any in couple decades! On one of my burn-rate charts it shows this;
#210-IMR4831
#212- N205
#218-H4831
#221 MRP

What cartridge data do you want. I have original Norma manuals available though the new cartridges obviously won't be listed.

N-205 was generally very similar to RL-22/Norma MRP. It also exhibited the same significant lot-to-lot variations, so be sure to check the markings on your cannisters to determine if they are all of the same lot. If not, segregate them into identical lots and if/when you change from one to another be sure to rework your loads. Use H-4831 loading data and anticipate that you'll be able to increase the maximum loads by about 2% by weight. I think you'll find that the 2% increase pretty closely follows what you would expect from RL-22.

Many, many years ago I bought a cannister of N-205 (then regarded as some kind of super-powder) and used it in a .264 Winchester to get great velocities with apparently moderate pressures. When I ran out, I bought another cannister and it popped primers (and delivered less velocity) than the original batch. Be cautious.

I just got around to using up a cannister of N-205 that came from "lord knows where" in some 6mm Remington loads. It is yeilding excellent velocity and accuracy in them.

By the way, your cannisters of N-205 are not a pound, but rather 400 grams -- 54 or so grams short of a pound.