I am fairly new to casting, been collecting for a while, but haven't done much casting.
Anyway, I am curious to why almost all of the commercial bullets available are "undersized". Most everyone I know recommends .357 or .358 bullets for 9mm, yet almost every commercial caster has .356 bullets available. It is the same for all calibers, with very few offering .001 or .002 "oversized" bullets.
I have never seen a 9mm not chamber a .357 bullet, well I haven't seen one not chamber a .358 bullet for that matter, so why wouldn't they size properly to prevent leading?