I've browsed the wiki and cannot find a definitive answer on how to do this. I can reverse engineer vehicles just fine (drive into factory and select manage > reverse engineer). However, no matter what I do, the game does not recognize guns for reverse engineering.

I have tried:
- dropping the guns on the ground in the little rectangle next to the shipping container in the factory
- dropping the guns in the shipping container in the factory
- driving a vehicle with guns in its inventory to the factory, right next to the shipping container
- putting the guns in the warehouse

Help?