Press 'S' to switch to the shotgun and space to fire the shotgun. Press 'P' to swap to the pistol and 'K' to shoot the pistol. And press 'M' to swap to the M-4 and 'F' to shoot the M-4.
this was just something I decided to make with this cool project I found by @gowen68. Thanks and check out gowen's gun sim too!
