There's lots to consider, so I don't think there's such a thing that exists as "best", for everyone. You are getting, and will get, lots of good recommendations, but they should be looked at as starting points. If you can find a range that rents any of the suggestions, that's the first thing I'd start with.
I don't know, for reference, what size/type of person or body style you are.
@fatboyroy has concerns and points that lead him to carry a different weapon than many would consider, but they're valid for his wants/needs. Others have different reasons to carry something else.
The type of holster and how you plan to carry are also HUGE factors - like
@fatboyroy said a large gun is cumbersome, I had a similar feeling until I went to IWB (inside the waistband) carry, with a Crossbreed holster, and it changed everything for me. Others may disagree with my choices, but they fit MY needs much better.
I used to carry a Springfield XDS, which was something people were high on as a carry choice. It flat-out sucked for me, as I couldn't confidently operate it without dropping the magazine, either on the draw, or a few shots into the magazine. It went from a good suggestion to something I got rid of, as I couldn't count on it. Gotta start somewhere though, and it wasn't a bad start - my wife liked it, and we would have kept it if she didn't LOVE her carry weapon even more.
I would check to see if Crossbreed makes a holster for the suggestions here - you will see what the difference is in types of carrying too - and start from there. I cannot recommend that company enough. If they don't have a holster for your choice, they can work with you, or may have one in the works.
Red dot is a great suggestion as well, but will make it somewhat larger and may add potential for printing and less concealed carry. Try to test it out, but it really will help tremendously if you're ever in a situation to need it.
Last thing I would point out is a way to practice, otherwise you may end up doing more damage to yourself! iShot, Mantis X, etc allow you to practice at home, practice your draw, practice ranges with your weapon.
I didn't offer you any suggestions, for the reasons above, but I'm a fan of Glocks. They most definitely are not for everyone, and their double stacks may not feel comfortable in your hand at all due to the size, but they do have single stacks that you might like. This, alone, is why I said to try to test/rent several, and see what feels good to you. It very well may change, like it did for me, and you have spent a good amount of money on a "best" setup that turned out to stink - for you. I can EASILY conceal a Glock 17 - and would prefer mine carry all the time - but it's not comfortable for long-distance driving. I use it 25% of the time for that reason. For long distance driving, I have a Glock 48, and a 43X. Sounds weird, but the 48 is a "summer" gun, and the 43X is for when more clothes are worn. The 48 is the one that feels slightly less comfortable in my hand, but it's my compromise for the situation that I still feel comfortable with - your comfort should always be first and last in the decision.
You have great suggestions to start from in this thread, enjoy the process!
ruger.com
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