Back in the day when revolver were still widely carried, for a time we were required to shoot a 50 round qualification with DUTY ammo even in off duty and backup guns.
Standard duty 38 ammo at the time was the 158 +P Lead SWC, either WW or RP.
However, it was found that this ammo was a little hard to shoot for 50 rounds in the Airweight S&W "Chiefs"...
So Factory 148gr Wadcutters were authorised for them.