Im building the M1A1 and trying to figure out the correct color. Ive done alot of research on the net but seems like there is about five different shades for the desert scheme . Is there a right one or is it kind of up to me to which color looks best?
Testors Model Master Desert Sand FS33722. This one is standard, but the light yellowish sand color is subject to fading and tint variations based on the amount of desert dust on it.
Well, there probably are about five different shades by now. The sun and weather tend to have a fading effect on paint so any sand-type color that is within five shades of the Federal Standard Tan color for U.S. Military vehicle Desert Scheme should be fine. The accuracy won’t suffer. Both the right color and what you think looks best will both be accurate, unless you choose a hot pink of course! 
I’ve standardized on Model Masters Acryl “US Army/Marines Gulf AR 1/2”. Just wish it came in BIG bottles. I’ve used it on 10 vehicles so far. Only 4 to go!
see almost done M-1 thread. I just used “poly scale model railroad colors” sand for mine. looks ok to me.