The last major US upgrade of the M48 tank series was the M48A5. This conversion upgrade was applied to M48A3 versions still in service with Army National Guard units in order to maintain the training levels of Guard units as well as using a commonality in ammunition amongst tanks. The upgrade featured the mounting of the M68 105mm gun carried in the M116 mount and the all-metric measurement M16 fire control system. The hull was upgraded by applying the M60A1 RISE Hull PIP Update Kit and incorporated as many of the components as possible. Some of these included the retrofit of the AVDS-1790-2C RISE diesel engine incorporating TLAC engine panels coupled to with a CD-850-6 cross-drive transmission, a 300-gallon fuel capacity and the T142 track assembly, M13A1 NBC protection system for the crew and the replacement of the .30 caliber M37 coaxial machine gun with the 7.62mm NATO M219/T175 machine gun. Because all M48A5 tanks were conversions from earlier models, many characteristics varied among individual examples of this type. M48A5 tanks could have either three or five support rollers on each side and might have either the early or later type headlight assemblies, some retained their earlier cupola styles.