Pricing Magic Bullets

[Sophie-Tiphaine Alouette]

I'd like to make sure I'm making all the correct assumptions on pricing for PFS play.

Bullets cost 1gp/per (UC)
Gunsmithing feat allows for making your own bullets (with a gunsmithing kit) for 1/10th the price.. or 10 bullets per gp (UC)
PFS Additional Resources confirms reduced price for bullets.

Magical missiles are priced per batch of 50, but (this is my big assumption) don't have to be bought in batches of 50.

1/50th of +1 enhancement is 40g for 1 +1 bullet.
1/50th of a +2 enhancement is 80g for 1 +2 bullet.

so, if I wanted to buy a +1 bullet of humanbane (+2 enhancement equivalence) it costs 80g and 1sp? or I could buy 10 of them for 801g?

Furthermore, such a magic bullet can use a normal charge of black powder.. same stuff as completely nonmagical bullets.. yes?

[Doug Miles]

Your big assumption is incorrect, sorry. You cannot prorate ammunition any more than you can charges on wands. The exception is if the item is on a Chronicle sheet. You would also need 27 Fame to be able to have access to the Bane enhancement (8,301gp).