Cannon-Caliber Electromagnetic Gun launcher
ARL testing
#### ARL testing

The ARL testing of the CCEMG launcher IIA took place at the EM Facility at the Transonic Range in [Aberdeen Proving Ground (APG)](/wiki/Aberdeen_Proving_Ground "Aberdeen Proving Ground"), MD. The launcher was powered by a 1\.55 MJ capacitor\-based pulsed power supply composed of eight banks, each of which could be charged to different initial voltages and be triggered independently in time. Throughout testing, muzzle velocity was measured using various techniques, such as by recording the time rate of change of the armature's in\-bore induction field. Other methods included the use of a [smear camera](/wiki/Smear_camera "Smear camera"), flash x\-ray, and radar. [Radar](/wiki/Radar "Radar") was also used to evaluate the subprojectile velocity degradation that occurred over the flight range. Fifteen yaw cards that served as cardboard targets were used to assess the free\-flight [aerodynamics](/wiki/Aerodynamics "Aerodynamics") of the projectile launched from the railgun.

The launcher fired a total of 39 shots at APG, where shots 1 to 9 focused on component characterization, shots 10 to 16 focused on armature development, shots 17 to 27 focused on launch dynamics, shots 28 to 32 focused on pseudo multishot capabilities, and shots 33 to 39 focused on peak performance. Shots 28 to 32 were fired without bore maintenance between the five consecutive shots to gauge the eventual multishot operation of the CCEMG launcher. During shots 33 to 39, launcher IIA was subjected to maximum stress levels by increasing the initial capacitor charge voltage and the resultant peak current delivered to the launcher. Consequently, shot 39 demonstrated the highest performance with a peak current of 766 kA as well as the highest muzzle current at 384 kA. However, since the launcher was not designed to withstand this level of force at the muzzle, substantial structural deformation and rail wear at the muzzle were observed afterwards. At the conclusion of the test, it was determined that launcher IIA was rendered unusable due to the resulting damage, and the remaining flatjack was pressurized to failure to determine its upper design limit. The flatjack reached a pressure ceiling of 30 ksi without failure, but the pressurization stopped shortly afterwards to prevent damage to the augmenting rails, which was salvaged for reuse. Upon the disassembly of launcher IIA, several cracks in the sidewalls were observed, likely due to stress concentration. However, the rail bonds and the aluminum\-coated rail bore surfaces sustained very little damage.


How many shots were fired by the launcher at APG?