What caliber are you comfortable with?  What kind of gun do you want to carry,  a Smith & Wesson 38 Special airweight or do you want to carry a full size Beretta 92 Brigadier.   I always tell my students that when they are choosing a firearm, they really should be realistic about what kind of threats they anticipate.   If you are carrying for your business and carrying gold or lots of cash, you may want to wear a bullet proof vest and carry a full size auto.  If you are a civillian that is just wanting to have the ability to carry and defend yourself, a 5 shot revolver may be more confortable to carry.

When I get my students to the range, I always start off with 38 Special revolvers.  I show the difference in recoil between airweight revolvers and something like a Smith & Wesson Model 19.    Just because the gun is smaller doesn’t mean that it’s easier to control, as we work our way up the chain of firearms, the next we use is a Kahr PM9.   I think it’s extremely reasonable to carry atleast 1 handgun magazine and Kahr magazines are meant for Kahr firearms.   If you are driving in a vehicle, I also suggest you keep atleast one loaded magazine in the vehicle.