Well bob, there is no magical round that will punch one hole at 100yds. Not that a 6.5 isn't capable of that kind of accuracy. There are just many more variables that go into it than just caliber. Quality of barrel, action, optics, ammo, and we havn't even got to the shooter yet. 6.5 seems to have a pretty good reputation and would probably do just fine. But so would a barrel full of other calibers. I'd say pick the one that interests you most and go to work with it. For what its worth I have a bunch of Contender and Encore barrels and the only PISTOL I have ever punched one hole groups at 100yds with is a 17HMR. And that was an exceptional day, not the norm. Don't set your expectations too high, any thing under 1" is good. Any thing under 1/2" is great. When you hear people talking of one hole 100yd groups, most are refering to the best they have gotten and not the average they get. Shoot, if it was that easy it wouldn't be any fun. I'm sure there will be some posts come in hollering that they get one holers all the time, And they just might, but unless I see it I'll just take it with a grain of salt and go on. That kind of accuracy just isn't that easy. Just my $.02 KN