At 50 rounds a month, a detective will live longer than you will. As long as you aren't trying to make it into a magnum. If not abused a Detective will last a very long time. I have one from the 1930s that works just fine. Just use standard 38 special ammunition and avoid the +p junk.
Mark Lane to William Buckley: "Have you ever referred to Jessee Jackson as an ignoramus?"
Buckley: "If I didn't, I should have"