I've been shooting quite a bit of this from my M39 lately. It's giving me very solid groups and is my current main practice ammo. I'm buying a spam can of it this weekend in fact. This early stuff seems to have a hollow base bullet of about .310." I suspect that will make it better for the tighter bored Mosins like mine.
I don't know if the primers are corrosive, but assume they are and do the usual cleanup the same day as the shoot not a month later. The Polish is shooting quite clean, apart from that. Much cleaner than Albanian, for example.
Zero hangfires out of the 100+ tested so far
The stripper clips its comes on aren't the best, but aren't the worst either. Just remember to grip the sides when you push down or it may "spit" a middle round out and force you to start over.