I was hired by Elyria, OH PD in September 1972. The Dept. had .38 Specials with blue or nickle finish, 4 or 5 inch barrels. The four of us who were hired at the same time were directed to go to a sportsmen's shop in Elyria, where we got Model 10-6's.
The load at the time was .38 Spl. RNL, and the ammo was quite old. One of our officers went to a call where the guy who was the subject of the call, pointed a gun at the officer and fired missing him. The officer fired back. 1st round barely made it out of his gun, 2nd round made it further, and the 3rd round struck the guy but bounced off of him. 4th round put him down.
It was determined that we needed new ammo

, so the FBI load was bought and issued.
When I made firearms instructor along with another officer, we qualified every 6 months using the FBI load, and then bought new ammo for everyone.
We eventually purchased 4 inch Model 66's for patrol, and 2 1/2 inch 66's for detectives and other personnel, and stayed with the FBI load, as the City didn't want us using .357 Mag. ammo.
After the 66's, we were issued Sigs. 226's for patrol and 225's for detectives and other personnel. The load was 9mm 249 grn JHP.