The Little Boy was seriously overbuilt. The W9, W19 and W33 warheads are examples of gun-type bombs similar to Little Boy with comparable cores and yields, bu

The Little Boy was seriously overbuilt. The W9, W19 and W33 warheads are examples of gun-type bombs similar to Little Boy with comparable cores and yields, but in much smaller packages. A gun-type bomb doesn't require a very complex system to set it off. The complicated bomb was Fat Man, an implosion bomb, that required very precisely calculated explosive lenses and precise timing circuits.