Two of my colleagues, at my station, on my shift, still carry S&W revolvers. I think several others on day shift still carry sixguns. I carried either a Model 19 or a Model 66 in my duty rig until 1997, and sometimes wish I had stayed with the sixguns. I still see plenty of sixguns in the holsters of older officers at my PD, who work for other divisions, particularly those in support divisions, but quite a few still on patrol. The 4" .357 sixgun was standard until 1997, when the standard became DA .40 autos, but nobody had to switch; existing weapons, whether revolvers or autos that were not on the list of DA forties, could be "grandfathered" indefinitely. Autos, particularly .45 ACP, were popular choices before 1997; I grandfathered three 1911 duty pistols until 2002.
We buy our own duty firearms, a common practice in this region of the USA, even for large agencies.
Admittedly, a double-column auto is a better choice for simple efficiency of space on the duty belt for the weapon and ammo, as we must now carry so much more stuff. My duty belt has not increased in available real estate since I was a rookie 27 years ago. (I eat no more than two or three donuts a year.
. )
I avoid specifying my employer, due to rules about using social media, and rules about publicly discussing certain subjects whole being a member of my PD. Clues: it is a BIG city, in the southeast quadrant of Texas, with thousands of officers.