Considering that you have a long large frame pistol mag in play, there is a much easier way to skin the cat instead.

Just long load the 9mm ammo so  it both fits the mag correctly front to back for clean feedings, and the COAL of the round has the bullet jumping about .003" to the leade.  Hence differences of the cases is only .546" and even with a 115 bullet, you still pull this off with plenty of bullet still in the case at crimping.


And going to end up with round that the COAL is just a touch longer than the below round.


Hence normally its the case mouth to the end of chamber that dictates head spacing, but when you long load the bullet so it has a short jump to lands, then this keeps the rim in the correct position on the bolt when the round is chambered  isntead.

So to pull this off with the bullet type your using, long load a round without primer or powder, smoke the hell out of the bullet with a marker, then chamber and try to lock the bolt up on the round.  Extract the round and shorted it until you can get the bolt to lock up on the round with just the hint of kiss to the rifling in the bullet smoking, then shorten the COAL about .003", and double check to make sure that the bullet is not still embedding into the rifle at load.  Once you have this long loaded lenght, then this will be the COAL for that bullet type, and better yet since you have gained case volume under bullet set to that of the 9X23 case or more, you can use 9X23 loading data.

Another option, would just be to set the barrel back.  Most of the barrel's as threaded 24 pitch, so every rotation the barrel is set back would be .0416", with your target set back at .546".

So barrel face and shoulders set back .5408", will end up with 13 turns back on the barrel in a 24 pitch; with the chamber now at .7592" and close enough for the 9mm chamber that the max case lenght is .754" instead.

Case lengths is you need them,

http://saami.org/specifications_and_information/publications/download/Z299-3_ANSI-SAAMI_CFPandR.pdf#page=10