No combat vet here, just 23 years [and counting] of full-time LE. Naturally, I'm issued a rifle, but also a shotgun. The M4 is fine, but my problem is that the rifle is in my patrol car's trunk, while the blunderbuss is in the car with me, and thus more quickly accessed. If there's time, I'll take the Colt, but sometimes, there isn't time [my last armed encounter was a prime example]. There have been several occasions in my career where just the sound of me racking that first round into the chamber of the 870 was enough to end all hostilities. That suits me just fine; if I can do anything to solve a problem without actually pulling a trigger, wonderful. Of course, I know better than to depend on that happening every time, and I don't. Still, it's almost a given fact: When that unmistakable sound is heard, everyone in the vicinity knows that things just got SERIOUS.
Seen on a bumper sticker: "Exercise. Eat right. Take vitamins. Die anyway."