right, basically this is the method that i used to paint my bar10. The following example will be a type of desert digital, but it will be relatively simple to achieve the same result in ACU or Woodland etc.....
Right, the materials you will need:
Page from maths book or graph paper for more precision/knife or scissors/Paint(krylon is preferable, but they are quite hard to find now. Duracoat of Plasticoat are alternatives)
Cut out some templates. (you can use the same templates twice, but i find the bigger the rifle, the more templates are necessary) i usually use darker paints further into the process.
the darker the paint that you are using, the smaller the template.
second, spray the object a base colour. (sand for deset/green for woodland)
Let it dry for about 15mins. also be sure to shake the paint for a good two mins before use.
when you have a good base coat, take your larger templates and lay then over the object, and apply med brown.(once you have sprayed, you can also move them around to achieve more shapes. Again, give it 15mins.
Once it is dry, take your smaller templates and dark brown, and begin to spray make sure there is less of the darker colours on the object.
And your finished!
another thing you can do after the the paint has dried (i personally do this with every gun i spray) is spray a very light layer of brown over the whole thing. it make the pattern a bit less striking and tones it down a bit.
COLOUR GUIDE:
desert=sand or khaki/med brown/dark brown
woodland=olive green/sand/med brown/dark brown
grassland=green/sand
PLEASE NOTE THAT THIS IS MY PERSONAL METHOD OF PAINTING. THERE ARE ALTERNATIVE WAYS TO DOING SO WHICH ARE EASY TO FIND ON GOOGLE.
however, i am open to questions, and i hope you find this useful.
EDIT: another thing i have found with krylon, is that if you wait for 5 or 10 mins, the paint has joined together, but not much to the rifle itself, so if you want a battered look on your gun with thowing it out your window several times, use you fingernails to tear off some of the paint. this makes it look like it has seen amny a skirmish!