As for that Czech stuff, I remember buying half a case of Czech FMJ a few years ago and if memory serves me correctly, it was manufactured by S&B, steel case and indeed Berdan primed/corrosive. I only put it through a Chinese paratrooper SKS I used to have (and cleaned appropriately afterwards), though I distinctly remember it being surefire and quite accurate as I always find Sellier&Bellot ammunition to be. I remember this vividly as I made quite a few lemon-sized groups at the 100-yard mark with iron sights (I'm usually only capable of melon-sized groups an SKS, let alone a paratrooper model SKS). If it's this same fodder but packaged on stripper clips (mine weren't), other than requiring a couple extra minutes of cleaning afterwards, it's great stuff!