01 Three Inch Main Gun	02 Aft 3 Inch Gun	03 Aft 3 Inch Gun Mount	04 Three Inch Gun Breech
05 Three Inch Gun Breech	06 Three Inch Gun Breech	07 Three Inch Gun Bore	08Three Inch Gun Bore
09 Three Inch Breech Block	10 Three Inch Gun Sight	11 Three Inch Gun Sight	12 Three Inch Gun Sight
13 Three Inch Gun Sight	14 Ranging Computer	15 Ranging Computer	16 Optical Gunsight

Shell Weight : 13lbs
Shell Types: HE Fused AA, HE Radar Fused AA
Barrel Length: 150.25 inches
Muzzle Velocity: 2,650fps
Horizontal Range : 14,600yds
Vertical Anti Aircraft Range: 29,000 feet
Rate of Fire : 50 Rounds Per Minute Max
Gun Mount Weight: 7,345lbs
Crew: 11

A single static Mark 21 Three Inch Gun Mount can be found at the Buffalo and Erie County Naval & Military Park in Buffalo, NY

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