I worked 20 years in law enforcement and have, at one time or another, carried a Colt Commando .38, Beretta 92, Glock .40 and for the past 11 years, a genuine 1927, 4-digit serial Colt Hartford Argentine .45 Auto that I custom built.
I like the old cap & ball revolvers and keep one in the car almost all the time. I have been in situations where I had two suspects at gunpoint with a 5 shot 38 and I never felt outgunned.
Most shootings are over in a few seconds with one or two rounds fired. The 1986 Miami FBI incident and North Hollywood robbery are exceptions and you probably couldn't carry enough ammo, or guns, for either of those situations.
I often put a 1860 Colt Sheriff's in my belt while walking to the ATM...FWIW