Please next time go to Help section
In-Topic : DSR Black Snake is for all who reach 20 Mega cap bought, those there and ak-47 blacksnake. if you dont have ak you wont be able to get dsr. dsr is free if you reach 20 Mega Cap..(Or is 21, i dont remember :P ) .
BlackSnake is out of stock so if you get all you wont be able to get dsr as you need ak-47 first.