i don't know if i'm right but souls of purgatory are like 盒式磁带, 墨盒 for God-castiel...but this weopons gonna empty after god-cass'll killing all his enemies in heaven?

maybe i misunderstood...but it seemed that castiel needed souls to arm his weapon and killed raphael...so each time he killed 或者 gonna kill someone he 迷失 cartrigde, his weapon will ended to be empty?...am i right 或者 wrong? am i misunderstood something in the explanations of 6th season?