Boom Town is a mock settlement set up for the express purpose of testing the performance of Saturniteartillery shells. It is paired with X-7a "Left Field" artillery launch facility. The entire area is irradiated as a side effect of weapons testing, with craters full of green radioactive material.
A strange cask (wooden barrel) can be found on top of a hill (outside the fence) just northwest of the footlocker with the recipe for the Guns skill book. Inside and on top of the cask are 4 bottles of battle brew. To get there, go northeast and up and back around.
The term "boom town" is military slang for artificial settlements they would build and fill with houses, cars and mannequins to see how atomic bombs would affect them during nuclear testing in the 1950s and 60s.