First, create an event, 'while a key is pressed' then choose the key, put in begin, 'if (weapon) is Showing then (weapon)' or '(vehicle of weapon) move left 0.27 (in my case)' then put the same just backward, instead of left, right.
When you hold the key you set in your game, it'll work.

You want to learn how to use magnified scopes?

HELL YEAH! I'm not advanced, im intermediate, ok, just because im asking for help doesnt mean anything.