Armorer
A modern armorer is someone whose job is repairing, assembling and testing of small arms. Originally, an armorer was a person who created armor for medieval knights and noblemen. Today an armorer is someone who belongs to an organization such as the police or military and who maintains guns and weapons belonging to that organization. An armorer keeps these weapons in top working condition always ready for trouble-free use in the field. By doing this an armorer extends the service life of these weapons at minimum cost to the organization. A failure of a weapon in a crucial situation could cost lives. Their job is similar (but not the same) as that of a civilian gunsmith.