Auscam has always been a little difficult to portray but lately I have come up with a mix that seems to work-
1. under coat with gw chaos black spray.
2. Overall coat of tamiya deck tan.
3. Small spots of gw cam green
4. Small spots of gw catachan green
5. Small spots of gw vermin brown
6. Small spots of gw scorched brown
Keep the spots uneven and leave enough unspotted tan to give it some definition.