The conduct of the Small Arms Firing School and National Matches as well as support by the U.S. Army are mandated by Federal Law. These events were create to train better marksmanship skills in service personnel as well as the civilian populace.

Read more of this legal requirement:
USCODE Title 36 Subtitle II Part B Chapter 407 Subchapter II Section 40725-40727
https://www.scribd.com/document/319156325/US-Code-for-Marksmanship-Events/