Inspired by all this chat, I went on Netflix and played some of the early 50s Dragnet episodes. I was immediately impressed by how low the production cost must have been. No action sequences, no fancy sets, and mostly dialogue taking place in an interrogation room, office, living room, etc. along with simple plots. A young Lee Marvin was in the S1E1 as a murderer. Otherwise, I did not recognize any of the supporting cast actors.

There was some gun and ballistics lore in a couple of episodes I saw - one featuring a M1911 used in a wife's suicide (which looked like a murder), in which the husband was cleared by the appearance and location of the fired casing (and some other evidence). Another was a murder made to look like a suicide, in which a Winchester M94 .30-30 was used. The bullet trajectory made suicide impossible and the murderer was caught.

Anyway, there was enough of interest in the gun sense that I may watch a few more episodes if I get bored.