This is hard to come by so it is worth the share.  I have been to every Home Depot and Amazon and tests many different colors of “Camouflage” spray paint.

This is the correct Green base of anything you are printing looking for a good Olive Drab background.

Aervoe 987A – 34087 WWII Military Flat Olive Drab Aerosol Spray Paint – 6 Pack

I can’t find single cans.. and I can’t find it anywhere else.  This guy has cornered the market.

This is what I use on all of my Artillery Shell prints.

Happy painting!