My father was a cop from ‘55 - ‘85. Couple of years in Pasadena,CA with the bulk of it in Richmond, CA, a true shithole.
Back then all patrol cars had a shotgun, the sidearm was a .357. Sargents had a tear gas gun in the trunk.
The "Newhall CHP Incident" of 1970 and the "Miami FBI Incident" proved that to be insufficient. Since then LEO's went to semi-auto pistols and AR type rifles.
I'd be willing to bet the Coward County deputy had a Glock of some caliber. A weapon of any type is useless though if the LEO is unwilling to close with and engage the shooter.