You’re right — there was a rifle range under Camp Randall, and it was linked to the UW’s Air Force, Army and Naval ROTC programs.
The range was actually part of a larger complex of military-related facilities that dated back to 1938, when Camp Randall was expanded to include two dormitories for military trainees under the east-side stands, along with wrestling and boxing quarters. The dorms were eventually named Schreiner and Baumann in honor of two UW students who were killed at Okinawa. More than 150 male students lived under Camp Randall until 1951, when the rooms were converted into athletic and military offices.
The last shots were fired in Camp Randall on May 28, 2004, when the range closed as part of the first phase of the most recent stadium renovation. The space was converted to a band and seat-cushion storage area, and the ROTC programs now use an off-campus facility for rifle training.

A student takes aim at the now-defunct rifle range located under the east section of Camp Randall.