Unsatisfied with the accuracy of his 1940 reading, Bob Feller arranged to measure his speed again, this time with a more advanced army chronograph. On August 20 1946, the test occurred, using a special “Lumiline chronograph machine” which the Army was now using to measure the velocity of artillery shells. This time, Feller’s fastball came in at 98.6 mph.

On August 20, 1946, the fastball of Cleveland Indians’ ace Bob Feller is clocked at 98.6 miles per hour by a U.S. Army device. The speed of Feller’s fastball surpasses that of Atley Donald, once clocked at 94 miles per hour.