This is strictly a hunch, but maybe it's Soviet Russian manufacture. The Novosibirsk LVE plant is famous for ammunition, notably the "Bear brand".
BR could be short for the Anglicized Russian word for Bear or maybe "Browning" as John surmised; NS would be Novosibirsk, and CC = Soviet Union, of course. (Ammo from Novosibirsk is usually stamped "LVE", but who knows what else they used?)
Check the case with a magnet, see if it is copper washed steel.