I took a concealed carry course ages ago, and it helped to instill a healthy level of paranoia about unintentional discharge.

My takeaways were:

• fuck semi-auto pistols. Many working parts means many points of failure; carrying with a round in the chamber is dangerous as fuck, especially combined with a hair trigger; even if you don't think there's one in the chamber, there's no good way to verify visually without opening the chamber, and even then people tend to give themselves a false negative and carry hot thinking they're carrying safely; if you don't carry hot, you have an extra step to perform under panic-levels of anxiety, aka you fumble with a gun-shaped brick for a couple seconds while your assistant proceeds to murder you; and blocky shape = blocky imprint = you've made yourself a target before a potential altercation even begins.

• Revolvers are the way cuz ^that. And the imprint is more varied, making it conform better to your pudge and not stand out through your clothing. But even among revolvers, fuck any that have an external hammer, which can get snagged on clothing or something, pulled back partially, released, and strike a round causing it to fire without even touching the trigger.

• Internal hammer, double-action-only is the way, cuz ^that.

• Load one round fewer than the cylinder's capacity, then close the cylinder with the empty chamber on top / in line with the barrel. Your gun is now only physically capable of firing by fully engaging the trigger. You can drop that fucker out of an airplane, and when it hits the ground it goes thud, not bang. Also, since the back of the casing seats further back than the back of the cylinder, there's a gap that you can look into to visually assess whether or not there are any rounds loaded; and where or not the individual chamber in line with the barrel is loaded (hot).

Absolute safest way to carry. Only downside is you only have 4 shots to work with, but if you need more than that, you're probably dead anyway.