Call of Juarez: The Cartel
51 Achievements
17-21h
PS3
Armorer
Unlock at least 10 new weapons in the campaign mode.
33.4%
How to unlock the Armorer achievement in Call of Juarez: The Cartel - Definitive Guide
Keep grabbing secret items and do the agendas and you should unlock this about mission 4. You need to be level 7 to unlock 10 weapons.
See Level 21. You should be able to get this by the end of Chapter 4 if you've collected most of the secret items & agendas.
See “Level 21 Achievement.”