I was originally going to vote 9mm because it’s such a practical round. It’s cheap. It has very manageable recoil even in subcompact handguns. It offers the widest selection of handguns made for that round.
But then I started thinking about which handguns I grab most often when I go shooting. Even though I normally grab a 9mm or .38special conceal carry gun to make sure I get some practice time in, I always take a .22 with me. So my vote is .22 and the reasons are: It’s dirt cheap to shoot. Recoil is so low you can focus on your technique much easier. Anything you learn on a .22 can be applied to larger calipers. It’s accurate, and you can buy a target style .22 handgun for much cheaper than a centerfire handgun with similar accuracy.
You can cast 2 votes if you want.