The number 21 symbolizes the highest military honor that can be bestowed. Originally the salute was 7 shots afloat but when land batteries advanced they could shoot 3 shots on land to every 1 afloat. Till it became that the highest honor shown was 21 gun salute. So any repetitive 21 is to reflect the highest honor, the 21 gun salute.
It correlates to the 21 gun salute. The ultimate respect shown to fallen soldier
Matches the 21 gun salute
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