i only used a shotgun once in a tactical situation, we stopped a car that was suspected of shooting up a wedding, a round hit the windshield, spiderwebbed it, by instinct i grabbed the shotgun out of the holder, opened the door and found myself rolling down a hill. i came up on one elbow from the prone position, fired one round at some guy putting handgun rounds into the cruiser while my partner was exchanging fire with another guy, the driver. he just, seemed to slip on ice and went down. it was later i discovered what i was even using, standard issue, well worn remington 870R. at that time, cool wouldn't have been a factor. a semi auto would have been better, its hard to pump in a new shell from the prone position. 2 3/4 in shell, double 00 buck, about 30 meters range