The forward assist (which is what you are talking about) as Magno said it to ensure the bolt is completely forward in battery, if you look at your bolt carrier group you will notice a row of indentions running down the length of it on the right side.. This is what the forward assist contacts and pushes the bolt carrier forward into battery.
You will typically utilize this after conducting a brass check or chambering a round out of your magazine.
You will typically utilize this after conducting a brass check or chambering a round out of your magazine.
