for a gen 4 23 or possibly gen 4 30 or 30sf. I like the gun and would like to keep it, but I want a larger caliber and don't have the money to purchase a new one without first getting rid of the 19. I love the size of the 19/23 platform and since I already have holsters for my 19 that I could use with the 23 it would make more sense to get the 23. On the other hand, I have shot my buddy's gen 3 30 and shot better with it than I did my 19.(go figure) That has me wanting to get a 30, but with my smaller hands the gen 4 or the sf model would be better. I have never shot a .40, but I know with enough practice it wouldn't be that big of a deal to get used to it. My decision seems to be coming down to ammo availability and cost. In my area .40 seems to always be sitting on shelves long after the 9mm and .45 have all been purchased. I think the cost difference on average between them is around $2-5 per 50 rounds.(not a huge deal until you start purchasing larger amounts) But I can't overlook the availability of the .40. What would you guys do?