Years ago, when people still put pen to paper, I used to correspond with all the classic names. Legends Elmer Keith and Col. Jeff Cooper were two.
On the subject of police weapons and loads, looking back it was kinda funny.
Elmer believed the ultimate police weapon was the S&W model-57 in .41 Magum. He liked the original police load of a 200gr. SWC @ 900fps, but when the police load was "warmed-up" to 210-grains @ 1,150 he kinda liked it. No over-penetration there!
"Better for shooting into the car, of fleeing bank robbers." Like a 1934 Ford with Bonnie & Clyde inside?
Col. Cooper believed every cop should carry a cocked & locked Colt .45 ACP, with military FMJ. I was constantly reminded, "it "knocks 'em down 90% of the time with one shot." "The 9mm was useless, and one of the reasons the Germans lost the war." K...
I told him once, that one PD used "stake-out squads" to curb robberies. Boy, did it ever! Usually with fatal results. The gun was the M2 carbine with & 110gr. soft-points.
Jeffco thought Thompson subs would be better, and they were around on the surplus market to law enforcement. Load of course: FMJ. The 90% thing and all that.
The shotgun was also a good choice. He liked the 12-gauge (Ithaca IIRC) and 3-inch magnum, 00 buckshot. Perfect choices for crowded "non & pop" groceries, or a a 7-11 on a Saturday night!