I agree H Depot nail gun shells. They're cheap and very good.I have tried the blank shells from Home Depot for the nail guns. The work fine and you don't have to pay for shipping. Look for a hobby shop near you. That is where I got mine and again now shipping charge. They were a little cheaper. The only thing I need is anyone out there know what is the correct O ring size. Is it a #10 or #11 O ring.