I'm really impressed with the accuracy of this gun stock out of the box. The only modifications that seem to make sense to me are the internal stuff. Of course you are going to need a smaller bore barrel if you are shooting small bore paint, seeing more and more of stuff on the small side made these days. No way to get any good accuracy shooting 683 paint out of a 690 barrel. So unless you have a good source of 688-690 paint, I would suggest picking up a barrel.