Oh, for the rest of your questions:
1. The terms are not mutually exclusive. You can have accuracy and precision in the same group (think tight group right on the bullseye)
2. I don't quite understand what you mean by overlap, but think you will answer it yourself after reading and looking at the picture I linked to.
3. Precision is a function of the rifle. Accuracy is a function of the shooter. You can have a precise rifle and not shoot it accurately. You can also shoot accurately with an imprecise rifle.
Making sense?