They are also known as the black truss markings. They provide a quick visual for the tape user and speed up the measuring process. Originally, 19.2 inches was used in metric layouts. Dividing 5 into 96 inches (8 feet) gives 19.2 inches, which yields five trusses per sheet. The black arrow in the photo to the right points directly at the black diamond located on 19.2. The red stud markings every 16 inches allow for a standard layout of six studs per 8-foot (96) section.
1 Minors under 18 must be accompanied by an adult at all times in the range and store. 2  You must be 21 years old to shoot a handgun & 18 years old to shoot a long gun without being accompanied by a parent or legal guardian.
Shooters under 18 years old must be accompanied by their parent or legal guardian on the first visit to complete the required paperwork and be issued a Range ID card. Once the minor has a Range ID card, they may use The NRA Range under the supervision of anyone 18 and older who also has a range card issued. The minimum age to use the Range is 7 years old and able to comprehend the written range rules.