You are all idiots. It's not a cap, it's a honeycomb cover used to stop light from glinting off the glass. Hell, that's not even a scope, it's called a CCO, and it comes standard with the honeycomb on the end.
dark youand canuck are retarded or some dumb as pog private soldier.... a m203 he round takes 50 rotations for it to arm 30 consecutive rotations determined by the rifled barrel. has a minimum arming distance of 25 meters so tossing it around wont arm it