Easy one : 3D printers are the advanced warfare "magic box", just use it 15 times, it spawn a random weapon, taking or not the weapon do not matter, one use cost 1000 points, rince and repeat 15 times.
Hence you have to earn 15k, it is very easy too, just circle in the roundish area but do not open more than one acces
The "active 3D" printer move like the magic box after several uses. You have a big map on the wall in the roundish area displaying the current active 3D printer. First one was always in the morgue.
You can this one easily after getting :