Actually although several people have mentioned that 5.56 round suffers from "overpenetration", the 5.56 round is less likely to overpenetrate than many kinds of pistol rounds. The 5.56 round transfers more of its energy to its target and tends to lose more velocity than many pistol rounds. Only armor-piercing type rounds (like the NATO green tips) will punch clean holes through a person without stopping them (as the rangers and Delta guys in The Mog learned). I would feel completey comfortable using a heavy (68-77 grain) hollow-point round. Also a patrol rifle can provide suppresive fire capabilities (base of fire & manuver, the most basic of small unit tactics). To those naysayers who disregard this capability take good long look at those poor officers pinned down in the LA Bank shotout. Those guys would have given their left nut for a patrol rifle. As for intimidation purposes, a Colt AR-15 pointed at you is pretty damn scary, even to the layman. With greater accuracy, less recoil, more ammunition, and suppressive fire capability, the choice is clearly in favor of the patrol rifle.