Burn,
As former LEO and current firearms instuctor, All I can say is that if you have an AR, carry the damn thing no matter what department policy says. Your life is infinitely more valuable than following some ridiculous policy. One of the departments I worked for had shotguns(yippee!!), unfortunately they were kept in the armory so you would have to drive back to the station if you ever needed one! What idiocy!!
In my experience, most Departments/Academies/SOs/ teach outdated (and occasionally dangerous) tactics and most LE Administrators dont know, and/or dont care, about the proper application of tactics or the characteristics of a fight. Therefore most policies they dictate in regards to the use of deadly force are not necessarily in line with keeping you alive until retirement.
Its is a fact that 70-80% of individuals that get shot with a pistol round survive. And if youre in a fight, the object is to win, not adhere to department policy. Period. Beanbags for shotguns????? I bet Platt and Maddox would have had a field day with that!
If I had to fight with a firearm, I would want to make sure it was the biggest thing I could bring to the party. As for rifles in pistols calibers, IMHO if youre gonna carry a rifle, carry a rifle.
If you are serious about carrying an AR, I would suggest that you contact Clint Smith at Thunder Ranch(830-640-3138 or www.thunderranchinc.com) and sign up for the Urban Rifle class. I would also highly recommend any of the courses, but for most LEO the best place to start would be with a Defensive Handgun course(I learned more there in a week than the Academy and 5 years of inservice training combined). The facilities and instruction are outstanding.
As for carrying a AR vs. just a pistol...
As Clint would say: "The reason I would use a pistol would be to fight my way back to the rifle I never should have put down in the first place."
Good Luck,
Goose
p.s. Please excuse any grammatical/spelling errors, I'm nursin a mother of a hangover...