I have some S&B .223 55gr ammo that came in a little 20rd green box. It says Made in Czech Republic on it. Anyone know for sure whether it's corrosive or not?
I don't think you can find corrosive 223 ammo if you went searching for it. The 223 was developed way after corrosive primers were discontinued. S&B makes good stuff, shoot it and enjoy it.
The only corrosive ammo I've seen recently was 8mm Mauser that was made in the 1950's. Yes, they are still selling it and it still works.
As for other calibers, you might run across some 7.62X39 made in E. Europe but everything from the Czech Republic is lead styphanate, the non-corrosive type.