Method: sponge camo job as shown here:
How to Camo Your AR15
Color: Rust Oleum Khaki for base, Rust Oleum Deep Forest Green (NOT ARMY GREEN, THAT COLOR IS PEA-GREEN!), and Rust Oleum Dark Earth Brown.
Base coat of Khaki across rifle and scope. Then once dry, approximately an hour later, took the Deep Forest Green and sponged it across the base to form roughly vertical stripes. Once the green was dry, then I took the Dark Earth Brown on a smaller sponge and randomly dabbed it over all the tan and green areas; it was literally random, I had no pattern in mind. Then once everything had dried, about an hour later, I used Rust Oleum Clear Coat MATTE (very important, if you use "gloss" or "satin" the gun will be shiny, and that's BAD) and applied 3 coats of clear coat.
All told, took about 5 hours (passive time), maybe an hour of active time. Cost was about $30 for the paint and sponges.