Rifle volleys are no longer a requirement at military funerals, but are still allowed if the personnel is available.
The fascinating story behind the military's use of the 21-gun
Air force honor guard 21 gun salute hi-res stock photography and
Mandela funeral: 21-gun salute is proudest moment for captain, Nelson Mandela
21 Gun Salute
Artillery Cannon - Last Salute
21-gun salute, Military Wiki
These US Military Funeral Traditions Honor the Fallen on Land, Air
Sailors fire a 21-gun salute during a burial at sea ceremony Wall
Old Guard battery provides presidential, ceremonial salutes with a
UVA reinstates 21-gun salute on Veterans Day after wide-scale backlash
Military tradition to be evident in Ford funeral events > Air
Three-volley salute at veteran Samuel L. Schwartz's funeral service