KEN TN said:Spray the base color first. Let it dry completely, overnight is OK
Spray the second coat and while still wet us Saran Wrap all wadded up into a ball to dab the paint off the stock. Practice this and remove as much as you need to get your pattern.
Spray the 3rd coat and repeat the Saran Wrap again.
Many of the Home Improvement stores, Lowes and Home Depot have FREE classes on Faux paint finishes and this looks like the technique for that type of pattern.
Just think you can tell the wife you are doing practice for a room in the house... Of course you need to buy a new rifle for each room and new finish you learn ;D
Have fun post photos of the finished product.