That's not to say that ARs are flawless. They still have a ways to go before they can replace my bolt-actions as go-to guns for big-game hunting, for instance. Compared with an elegant turn-bolt, the current crop of production ARs are heavy for their caliber, make too much noise when being loaded and are clunky and can be damned uncomfortable to carry. But dress up an AR for varmint shooting, as Rock River Arms has done with the new Varmint A4, and these drawbacks either fade in relevance or transform into assets. An AR's weight, which can be excessive in a deer-hunting rig, helps control recoil, mitigates barrel heating and lets the shooter spot hits on target.The small cartridges the AR-15-sized action favors are ideal for varmint duty. And the high-capacity magazines and an ability to make multiple, fast follow-up shots are just what you're looking for when facing a field full of ground squirrels on the move.