Many departments specified 38 Special over 357 Magnum for fear of public reaction to their officers carrying "magnums." My guess is that you one such example here. The 581/681 bravely carried on the tradition of the service revolver in the face of unrelenting sales pressure from Glock and S&W to replace revolvers with semi-autos. Then look to see how many times the departments have changed again.
IMHO, most officers were better-served with revolvers. Revolvers require fire discipline, something I do not see in many after-action reports on police shootings.
What, revolvers are old fashioned and 38 Special is outdated. Read up on Jim Cirillo, Bill Jordan, and the like and tell me they were outgunned. Skill (and determination) trump magazine capacity every time.