They show the hit men shooting revolvers with silencers. Because of the space between the cylinder and the barrel a silencer will not work on a revolver and must be used on a solid barrel, such as that on a rifle or semi-automatic pistol.
Stax takes out a pile of hundred dollar bills and counts off five of them that is supposed to be five thousand dollars. It takes fifty hundred dollar bills to total five thousand dollars not five which is only five hundred dollars.