Gun Site

A long building made of gray stone sits next to a smaller, rounded gray structure.
At Gun Site, researchers used a firing range to test the gun-type weapon design.


Quick Facts
Los Alamos, NM

This site is on Los Alamos National Laboratory property and cannot be accessed by members of the public. 

As theories and designs for the gun-type weapon developed, scientists needed a firing range to run tests in the field. A nearby ranch, known as Anchor Ranch, served this purpose after the War Department purchased the land. It included an assortment of typical ranch buildings, but also included a large, flat stretch of land perfect for gun emplacements. A bordering canyon provided natural protection for the control building.   

The firing range gave researchers a chance to study projectile movement, the effects of impact, interior ballistics, and more. Using a large periscope, researchers had a full view of the test range during shots. The site had one major disadvantage. It proved difficult to protect the nearby road during tests. Despite best efforts to blockade traffic, cars occasionally slipped through. Fortunately, researchers managed to carry off their tests safely.   

When the laboratory began to focus on implosion, early explosives efforts started at Anchor Ranch as well. Working with pentolite, the researchers soon discovered issues in exploding high-density charges of the substance. Their work underscored the inadequacy of current knowledge of high-explosives. Eventually, as the explosives program expanded, tests moved to S-Site.   

Continue Your Journey 


Behind the fence, Concrete Bowl and Quonset Hut TA-22-1, were important to the creation of the atomic bomb. Learn more about the history of the Manhattan by visiting the Bradbury Science Museum! The museum’s interactive exhibits share stories from the project and provide a glimpse of other “behind the fence” historical sites. 

Manhattan Project National Historical Park

Last updated: March 15, 2022