Hi rbose,hi all
To answer your question,yes they go bang all right,yes they're from the Czech republic,and yes they've been out for quite a while.When I started reloading a while back,of course I didn't know all the miscellany things and bits of info I gathered since,so when it came to primers,I took what was cheapest at the time(1K for a cent each)and they were S/B,the vendor at the time told me that he was nearly giving them away because otherwise noone would buy them,arguing that they were crappy or something...I got them, tried them,compared them with CCI 200 that I'd just bought a bit later,and could'nt see a notable difference in both...Some months back I went to that same shop and asked that same vendor about them,and he told me he had none left,and that at a cent a piece,everybody had finally discovered they were good to go...They're just as good as CCI in my opinion,certainly a bit different in some kind of way,but they sure do the job,their rifle brass is absolutely great if you get the chance to find some,and here where I live(New Caledonia) it's cheap;I wouldn't bother with their pistol cases,too weak,but their rifle ones are top material.Hope it answers your question.