When I first started shooting I could only shoot three shots before I was tired. After a few months of shooting I can shoot for hours.

I don't think that the release is the problem. It could be, but I doubt it. You might want to try shooting a string loop. If you don't like it you cantake it off.

There is some good information for the beginner on huntersfriend.com . Once your thereyou will see a catagory titled Articles and Help to the left. Click on those links.