Win the indicated battle on the map to unlock the corresponding weapon:

Oran - Chatellerault
Oran - Hatchkiss
Oran - Karabiner 98k Bolt Action
Oran - MAS 36
Oran - MAS 38
Oran - M1 Garand
Oran - M2.50 cal Browning
Oran - MK 2 Grenade
Oran - Stielhandgrenate
Oran - Thompson