Question is a little to general, but here goes.
If you are deer hunting or game in similar size, then a 3" circle would be probably OK, but if we're talking bushy tail hunting, then probably not.
I personally don't want a deer rifle, that I can't hit a poker chip with at 100 yards, and a rifle I can't touch the same hole with for small game.
I do my own loading for all my hunting rifles ( except for my .22's) so this kind of accuracy is almost always attainable ( If I do my part) but if you are shooting factory loads, then this kind of accuracy may or may not be, attainable for your rifle.
I would play with several different kinds of factory stuff, until I found the best accuracy that I could get, ( at least 1 1/2" at 100 yards) and thats what I would go with. Since shot placement is the MOST important, I would not worry to much about what kind of bullet I was using for the most part, as any bullet ,in the right place ,will pretty much be lethal on any animal you want to hunt.