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Lets say a .40 S&W Subsonic bullet moves at 1000 ft/sec.
So...
(1K ft)/Sec Converted to miles/hour
Equals 681.818 miles/hour
The speed of sound is approx: 340.29 meters/sec @ sea level
so...
340.29 meters/sec converted miles/hour
Equals 761.207 miles/hour
Killaz: