Best caliber for pistol cal carbine?

[17-21-23]

Been waiting a long time to get a pistol caliber carbine of some kind. I know most guns are 9mm, but there are .40 and .45 options as well. I have more 9mm than anything but could always trade it.

Which caliber do you all think is best for a PCC application?



BTW I wish the cheapest FN PS90 ammo wasn't nearly as much as bulk .308...

What ever you want. To many personal opinions with this one. This just goes back to the all mighty caliber war.

 

[792mauser]

I like loading my Uzi carbine in 9mm rather hot.