I wouldn't recommend primer either, it isn't designed to stand up to weathering, staining, etc. I painted a SAAB with a PPG Base/Clear and added flattening agent to the grey parts of the car. It gave a nice flat finish that went well with the glossy black the rest of the car was painted in. Talk to your paint supplier, they can give you way more choices that will suit your needs. Most paint suppliers have paints designed for military use that are flat. (Camo colours, including black)