I have been wanting to pick up a Glock for a long long time and before I 'pull the trigger' I have a couple of questions. I like the idea of using one gun for several hot calibers and the .40, 10mm and 357sig seem to be good candidates. I have a couple of questions about this. 1)What would be the best direction to go Glock23 in .40 with a (2nd)357sig barrel or Glock29 in 10mm with a (2nd)357sig (or even 3rd .40?) or Glock31 in 357sig with a (2nd).40? Is it possible to fire 10mm through the #23/#31? 2)How easily can the barrels be swapped out? Could I drop the barrels in myself in a few minuets or is that impractical?