Airfix 1/35 M1A2 Abrams(Trumpeter kit)

Well, most NATO vehicles are supposed to share the same scheme of Bronze Green, Leather Brown and Black (actually dark gray) cammo paint (to foil enemy intelligence who might deduce what unit is where by noting the "national" colors on their equipment, a leftover strategy from the Cold War). So you could use the equivelent Bundeswehr colors cited at the German camouflage color website:

are slight shade variations between the various national armies, but this should put you in the ballpark, at least. Alternatively, Tamiya makes the three NATO colors in their acrylic range. Gerald Owens

Well, an M1A2 is rather rare in NATO 3-color. You could go for overall sand. I also believe the Airfix kit is a reboxed Italeri M1A2, not Trumpeter.