I added a 40 SW pistol to my collection because simply put,it was the most beautifully finished non custom guns I had ever seen.
Now I will be trading that gun in for a gun that I can actually carry on me without it looking like I have a hunk of LOOK AT ME!!!!!! STAINLESS STEEL on my side.
The 40 SW was a new additional round to me.
I already had a .380,a .22LR and a 38 special.
Now I've added a 9mm to the mix.
I am paring down.
Unfortunately,to have a respectable amount of power in a semi auto,you really should have a 9mm so I will have a small carryable handgun in that.
Probably a Kel Tec PF-9.
Kahr's polymer guns cost more,have had similar problems than KelTecs and are marginally larger and cost more,way more.
And Kahr's customer service has had some issues.
All of my guns have to have a reason to be in my house.
Being pretty is nice but if I won't have a defense use for the gun,it goes.
I already have a Smith Model 10 guarding the house.
I have a 380 Mauser that has earned a permanent place in our family.
I have a Taurus Ultralight in case my wife needs a snub nose revolver quickly.
The 22 High Standard six inch revolver is something I can afford to let hang around and is good if I need to dispatch a varmint or two.
But my Ruger 9mm,which is a great gun and my Taurus PT101 40 SW which is the beauty,what a finish on this gun!-they have to go.
I don't have the money to own guns that have to stay home because they are simply to big to carry.
I'm leaning towards a KelTec P3AT first ( the Mauser is stainless and kind of heavy-plus it's a classic to me)then either a KelTec PF-9 or a Smith 442 lightweight no lock dao revolver.
But then again,a grinding wheel can make that Ultralight Taurus into a hammerless real quick for free.
So it might be two KelTec's.
Who knows?
Until you pay for them,it's anything you want to buy.
So my short answer is the same caliber-especially if it's 9mm-the cheapest practice ammo you can buy right now.