~ 10 years ago I converted Tokarev 9x19mm and Star Super B 9x19mm pistols to 9x23mm. With 158 gr bullets, the Tokaev will feed 1.36" and the Star will feed 1.29".
That is not with the standard 9x23mm reamer that Brownells sells.
That is with me throating them out.
The Starline 9mm Super Comp brass has more capacity and the Win 9x23Win brass can handle higher pressure.
But as I try to tell everyone doing the conversion, your pistol can't handle HALF the recoil 380 can make with loaded hot, so what makes you think there is any point in stepping up from 9x19?
There is this problem of your slide mass and your recoil spring are a wimpy combination.
If you have a slide mass of a magnum research Desert Eagle, you could find a useable increase of maximum power between 9x19mm and 9x23mm.
My father once said to me that the maximum recoil spring energy for a given volume of the spring is at 50% preload. This can be derived by ~~taking the equation for a spring, integrating over distance to find the energy in the spring, take the derivative and set it equal to zero. The top of the hump is when the slope is zero and that is with 50% pre load.
There is inadequate volume for recoil springs in a Star Super B, but I bored out my cowling on the bottom of the slide and made room enough to go to the next higher size in the Wolff gunsmith pak #14.