I like this Pella Bird 'n Lite strap vest, and they also make a full vest. The weight-bearing belt strap and side cinch straps are great for carrying the game bag weight. Besides the water bottle pockets, the big pocket on the back is good for carrying a Camelback water pouch -- I like this a lot to have ample water for dogs in the warm early season. Browning uses the same strap technology, but their version of the strap vest is higher with padding around the back side -- I like this better for being lighter and cooler.

http://www.youtube.com/watch?v=X6nwJ4OHYO8

I also have a small Quilomene vest with similar weight-bearing belt. It's designed for use with a Camelback, and worked great for me for years, but I switched for the added features of the Pella Bird 'n Lite.

Jay