Penetration of 60-Grain and 240-Grain Bomb Fragments into Wallboard

The primary objective of this program was to define a function between the striking velocity for 60-grain and 240-grain and 240-grain random shaped bomb fragments and their depth into the wallboard trade named Nu-Wood. The 60-grain fragments were fired from a 20mm Mann barrel and the 240-grain fragments from a 30mm Mann barrel into bundled Nu-Wood. The striking velocities for the 60-grain fragments were in the 600 ft/sec to 5000 ft/sec range and the 240-grain fragments in the 300 ft/sec to 3500 ft/sec range. The graph of fragment striking velocity as a function of depth into Nu-Wood showed a wide range of depths for approximately 2000 ft/sec. A least squares curve would not be valuable since the penetration spread is too wide at given velocities. Fragment penetration into Nu-Wood from firing cylinders does not give a realistic picture of 60-grain and 240-grain actual bomb fragmentation spread. The depth of penetration is not a primary function of the initial presented areas of impacting 240-grain fragments for 500 ft/sec to 3000 ft/sec velocities. When a factor of two or more exists between impacting presented areas for 60- grain bomb fragments, then the presented area seems to influence penetration.