The Department of Defense was formed out of the defunct Department of War in 1947 by President Harry S. Truman to reduce Interservice rivarlry between the branches of the Military, uniting all branches under one Department. The DoD quickly set out with its mission, creating the United States Air Force (previously belonging to the Army as the "Army Air Force"). Since it was also given control of the United States Military, the Secretary of Defense took direct orders from the President of the United States.
The Department of Defense quickly grew in size as the United States government was constantly worried about an Communist attack on either its soil or the rest of world. The DoD would be issued a "blank check" by the government as the Cold War progressed, allowing it to open new projects and agencies (such as the secretive DARPA research division). Meanwhile, the Department of Defense also dealt with numerous wars and conflicts, as well as dealing with the various commands in the Unified Combatant Commands around the world.
The DoD was ultimately in charge of military spending in the United States, they made various systems available to the different branches of the military.
This list only covers weapons that were entered into regular service, not weapons that had been rejected or not left the experimental/prototype phase.
- A6-16 Assault Rifle
- M1 De-Atomizer Pistol
- M18 Energy Rifle
- M200 Designated Marksman Rifle
- M45 DAPW
- MK II Tactical Checkpoint Carbine