This is the seventh partial report on test firing of 3 in.70 Caliber Single Mount Mark 35 Mod 0, and the final report on the Determination of Case Ejection Velocities in this mount. Rapid-fire life tests of 3 in.70 barrels have been under way for a considerable length of time. These tests have been and are being fired using ammunition containing a hot propellant or a cool propellant. These tests are conducted with the 3 in.70 Caliber Single Mount Mark 35 Mod 0 which is capable of firing at the cyclic rate of 90 rounds per minute. When firing rounds made up with the cool propellant an unusual increase in the velocity of ejected cases was noted visually. As a result the Bureau of Ordnance requested that a study be made of case ejection velocities. This report summarizes all such tests conducted to this writing and completes the case ejection velocity study.