Painting Trumpeters 1/35 T62 ERA Mod. 1972

I recently bought myself the Trumpeter T62 kit (1/35 - #01556), which is supplied with a metal gun barrel (not entirely sure if its aluminium or steel) which i would infinitely prefer to use over the plastic barrel which is a multi-part assembly. does anybody have any experience painting these particular parts, i am pretty sure that i cant just slap primer straight on to the barrel, but this is the first metal part in a model kit that i have come across (with the exception of photo-etch parts)