Jump firing test

Jump Firing Test. In tabulating the elevations azimuths required to obtain a given range and deflection of a gun, account is taken of the fact that usually the direction of the target to the trajectory at the origin differs from that of the axis of the bore of the gun before it is fired. This difference in direction is called jump. The jump may be in any direction, but as a matter of convenience it is described by two coordinates, vertical horizontal The jump firing test is described in US Ordnance Proof Manual 40-11 (1942)... 

I) Bu 11 et Fit(Jump) Test for Caliber. 45 Ammunition. When cal. 45 ammo is fired in a revolver, recoil of the weapon tends to cause the bullets in the unfired cartridges to move forward and, if the bullets are not held tightly in postion in the cartridges cases, they can jam the cylinder and prevent it from revolving. The test described in Ref 9,p 5 has the purpose of determining whether or not the ammo for cal. 45 jams the mechanism of a revolver when fired... 

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