Disarm 3 Enemies - Sharpshooter Challenge

I'm having a lot of trouble with this one despite always using dead eye and seemingly aiming on their hand or gun. I'm using 2x volcanic pistol, so maybe you need to use a revolver or carbine but that seems strange, any help would be appreciated!

Edit: Figured out the best method, go into dead eye for the for as long as you can to disarm them, but don't paint them with a marker, just aim normally and try and shoot the gun out. Then if your dead eye is used just attempt to shoot it out normally and don't go back into dead eye, as that will reload your gun. Hope this helps.