The time interval between rounds in a cannon
salute will be 3 seconds except as follows:
When honors are rendered at funerals, in
which case the cannon salute will be fired at 5 second intervals.
When such interval is in conflict with
prescribed safety regulations for the type of cannon employed.
When such interval is not feasible
considering condition of ammunition and materiel, number of guns available,
proficiency of gun crews, atmospheric conditions, and other local limitations."
"When 2 or more persons entitled to honors
arrive at or depart from an installation at the same time, only the senior will
receive honors.
Any official or officer holding 2 or more
positions (civil or military), 1 of which entitles him or her to honors, will
receive only the honors due the highest grade. In no event will the same person
be honored in more than 1 capacity."
I only saw 2 cannons that were being fired at the cemetery.
"Cannon salutes to persons.
The time interval between rounds in a cannon salute will be 3 seconds except as follows:
When honors are rendered at funerals, in which case the cannon salute will be fired at 5 second intervals. When such interval is in conflict with prescribed safety regulations for the type of cannon employed. When such interval is not feasible considering condition of ammunition and materiel, number of guns available, proficiency of gun crews, atmospheric conditions, and other local limitations."
"When 2 or more persons entitled to honors arrive at or depart from an installation at the same time, only the senior will receive honors.
Any official or officer holding 2 or more positions (civil or military), 1 of which entitles him or her to honors, will receive only the honors due the highest grade. In no event will the same person be honored in more than 1 capacity."
I only saw 2 cannons that were being fired at the cemetery.
Yep. The same day, POTUS Trump received a proper 21 gun salute (3 cannon, 21 rounds, 3 second spacing) after leaving marine one prior to his speech.