<P> The duties of the sentinels are not purely ceremonial . The sentinels will confront people who cross the barriers at the tomb or who they perceive to be disrespectful or excessively loud . </P> <P> Over the years there have been several different types of weapons used by the tomb guards . The changes in weapons reflect the changes in the Army, including M1903 Springfield rifle, M1 Garand and M14 rifles, M1911 and M9 pistols . Tomb guards currently carry M14 rifles, which are affixed to ceremonial rifle stocks . These rifles are cleaned daily and kept ready for use at all times . </P> <P> There is a meticulous routine that the guard follows when watching over the graves . The tomb guard: </P> <Ol> <Li> Marches 21 steps south down the black mat laid across the Tomb . </Li> <Li> Turns and faces east, toward the Tomb, for 21 seconds . </Li> <Li> Turns and faces north, changes weapon to outside shoulder, and waits 21 seconds . </Li> <Li> Marches 21 steps down the mat . </Li> <Li> Turns and faces east for 21 seconds . </Li> <Li> Turns and faces south, changes weapon to outside shoulder, and waits 21 seconds . </Li> <Li> Repeats the routine until the soldier is relieved of duty at the Changing of the Guard . </Li> </Ol>

How many are buried in the tomb of the unknown soldier