PENETRATION AND CRATER VOLUME IN VARIOUS KINDS OF ROCKS AS DEPENDENT ON CALIBER, MASS, AND STRIKING VELOCITY OF PROJECTILE
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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Firings of caliber .50, 20mm, and 37mm A.P. projectiles were made on 4 x 4 x 3 blocks of granite, diabase, quartzite, oolitic limestone, and sandstone. The results of firing major caliber projectiles on limestone at Fort Knox, Kentucky, were obtained from the Armored Board. From the results of the firings, relations were deduced giving the depth of penetration and volume of crater as dependent on the caliber, mass, and striking velocity of projectile. The observed penetrations were approximately inversely proportional to the cube roots of the compressive strengths of the rocks. Rock walls constructed of granite blocks were found to be inferior to massive monolithic granite due to the extensive spreading of cracks along the mortar bond. H.E. Type artillery shell with concrete piercing fuzes were observed to rupture on impact on a rock wall. Modified H.E. shell with thick cases, containing about 5 explosive, withstood impact on rock with deformation.
- Geology, Geochemistry and Mineralogy