How about back up guns? I have to believe that small autos were probably carried for reserve weapons. During that time 1920's - 1950, hell, I wouldn't be shocked to learn that some of those fellows were packing top breaks for a backup piece either. There was an old time detective I once knew, he retired around 1955 or so. By 1975, he was pushing 80 + years old and took ill one afternoon. He called and asked me to drive him to his Doctor, so I obliged.

When we arrived sitting in front of the Doctor's office in the car, he handed me a .38 M&P, a pair of brass knuckles, a small blackjack and said "oh, I almost forgot" as he handed over a Colt New Line .22 single action he had concealed in his shirt pocket. That ole' boy went about pretty well heeled.

I suspect an awful lot of LEO's from that era did likewise. I have always carried 2 and on "high risk" occasions, 3.