WWII U.S. Military AN MK-5 Practice Bomb

This is a AN MK-5 practice bomb, which was one of three similar miniature practice bombs used for low-altitude horizontal or dive bombing practice during WWII. Most examples of these practice bombs I have seen are the MK-23 cast iron version. The MK-5 is the much less common version which was the most expensive to produce using war time scares zinc-alloy. This MK-5 has an overall length of 8.25" and is made of zinc-alloy. The diameter at its largest point is 2.18". The fins are 2.5" in length. The weight, without the signal, but with the firing pin is approximately 2 lbs-9 oz. and when armed is approximately 2 lbs-11 oz. Inside this practice bomb was a AN MK-4 spotting charge, which consisted of an extra long 10-gauge blank shotgun shell that was inserted into the hollow chamber of the bomb. As was common, this bomb does not have any marking except for a R1 near the top. This example uses the two steel cup construction firing pin assembly, which is removable, which with inertia fired the MK-4 spotting charge on impact. This MK-5 is in excellent condition with scuffs and marks from storage with the firing pin assembly showing light surface corrosion and the cotter pin in very good condition.