Blake,
Where do you hail from? What type of area will you be policing? Rural? City? Also, what type of of ammo will you be carrying? Take it from somebody who has been in the business for 20+ years, all these factors need to be taken into consideration.....
1. When I first started, I carried a Ruger Security Six, mostly because I had to get my mother to purchase it because I was not quite old enough to by a gun or ammo. The only bullets I carried were .38's....The .357 bullet will travel through alot and you don't want to chance hitting something, or somebody, that you did not want to....
2. You might consider a pistol (automatic) in either 9mm or .40 cal. The 40's are one of the most popular these days for police work. Also, the automatic gives you more ammo if you were to need it. Think about it, carrying a revolver you would have 18 rounds of ammo, however, carrying, say a Glock 40, you could have about 46 rounds of ammo in 3 mags and one in the chamber. I know some guys who got into gunbattles and burned up a mag in a matter of seconds.
3. I did carry a .45 for awhile, and if I were still working patrol, I might still carry it. But working plain clothes now, I went back to the Glock 22 and carry a .38 revolver on my ankle all the time.
Just my thoughts on this.....Let me know how it works out...
Bob/TX