New Carry pistol, I want a 4" barrel 9mm single stack.

[Clark]

A Kahr P30 .380 loaded to 9mm levels with handloads is very small and carry-able.

Kel-Tec P3AT 380 and Ruger LCP 380 are lighter, but cannot be loaded to 9mm levels, due to poor case support.

 

[SharpsDressedMan]

The 4" barrel specification is going to exclude some of the compacts mentioned here.