Excellent information from all. My information in part is personal experience and some told to me. While a policemen in Wyoming and very wet behind the ears I carried a 6" Model 19, initially loaded with 158 grain .38 special ammunition, Speers I think. When a Deputy inquired as to my carry load, he told me those really weren't superb and suggested his carry ammo, Treasury ammunition from Winchester I believe. I fired them in and in my experience they had a bit more " git in their giddyup ", as compared to my civilian ammunition. I had no Chronograph and it was my ear as well as a slight increase in recoil.
Roll the clock forward and the agency I retired from in Fl had a great, at that time, staff of armorers who really took an interest in their jobs and the true training of their charges on the range. 10,000 pushups for anyone dropping a weapon on the range in the academy. Yep, one poor soul did and yes, he had to do them in the 15 weeks of training. Jeez, things were different in the " stone age ". Anyhow, one of the instructors from my agency assisted me with ammo one day while at our range on my time practicing and offered me a box of Federal Treasury loads he had gotten from FLETC while there for a training class and I found them to be just as potent as the Winchesters from a Decade prior. While we never were issued this ammo, the armorers tried to no avail, I was assured by all I encountered who did use it that it was effective but barrier penetration was lacking. On a side note, I read somewhere that several State Police agencies have issued the Plus P Plus .38 ammo in the past although not the 110 grain variety. Michigan Troopers used a 125 grain version. Alas, my agency generally issued whatever happened to be the " state bid " ammunition that particular year. We were all just happy it wasn't the LRN types as had been the issue in the past. Sorry to ramble fellas.