It is best not ot take any weapons in to Mexico at all, no ammo either even spent cartriges are prohibited.
Do not create a hardship for something so simple, Mexican jails are not nice at all, the inmates are the ones that run them, and it will cost a lot of money from the family of the incarcerated to be left alone in one from the rulling gang lord.
Go down as a simple TURISTA behave obey the laws do not get to drunk and be respectfull of the people and you will have very good and nice time.
I agree with briansue about the dumb coments at the begining of the post.
navegator