RE: got a couple ?s
A fast .22 will kill a deer if everything goes right, but they're far from optimal for deer hunting. A .243 is better but still not what I consider a deer round although many will argue with me on that one. In my opinion deer rounds start at the .257 caliber and go up from there.
If you're looking for a dual purpose round then logic dictates that you have to pick one adequate for the largest game you're hunting and accept the limitations it has on the smaller game. If you're buying a truck that's got to pull a 15,000 lb trailer once every six months and serve as a daily driver the rest of the time you don't buy a four cylinder nissan, you buy a big diesel since it's able to handle the biggest job you're going to throw at it. Same thing with rifles, get one that'll work for deer and use it for varmits. If you try to make a varmit rifle work for deer then you're asking for trouble.