As much as I love .40 S&W for Self-Defense, and as often as I carry my M&P40 Shield, the gun that's always on my person, even when I'm just walking around the house, is my Ruger LCP.
Depends on where I'm going but anymore my default gun is my S&W 640 no dash so it's 38 special. Once in a while though I'll carry a Kimber Aegis Ultra 9mm or S&W 3" Shield 2.0 9mm.
I like the .38 Super from a stainless government too.
The .38 Super was supposed to be the gang buster of the day. Made to penetrate the thick car bodies of the new mobile outlaw.
But wait, law enforcement was still in their love fest with the wheel gun and have you heard of this new round that makes the 38 Super look like a pea shooter? That's the dung heap that the .357 Magnum seeds were sprinkled over...and wow.
In the 70's most urban big city police departments had a lot of legal cement blocks to drag around. As you might remember, a racially charged atmosphere like a powder keg. Political and civil unrest combined with dense populations kept the .357 Magnum on the leash. At least officially. Anybody who heard the report and saw the muzzle blast probably had both pant legs wet and that don't play well at City Hall or the 5pm news.
I was handed a Model 10 department issue but had the opportunity to upgrade as long as my personal revolver was either S&W or a Colt in .38spl. My Model 10 stayed in my uniform holster....and my Model 19-3 got carried in BUG...with some Super-Vel JHP magnum loads.
Stainless was the way to go but it was still scarce and pricey. The working man solution for me was a new 19-3 that was sent off for trigger work and hard chrome plating.
How does hard chrome stand up to decades of abuses of EDC?
I'll let you be the judge.
9mm. Anything larger or heavier than a P365 and I tend leave the carry gun at home. Anything less than 9mm lacks the power to both expand and penetrate. Might give 30 SC a try if the right gun is chambered for it.