Test of 3 in/50 AA Projectiles with Copper Welded-Overlay Rotating Bands
NAVAL WEAPONS LAB DAHLGREN VA
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Tests were conducted to compare the metallurgical and physical properties and the ballistic performances of the 3-in.50-cal Mk 33 Mod O AA projectiles with Cu welded-overlay bands I and standard Mk 33 Mod O projectiles II. At proof or service pressure, I had better band engraving upon firing from a new gun however, in a worn gun at service pressure, II showed slightly better band engraving. Both bands failed at proof pressure in a worn gun. The cavity deformation under the band was greater for I. Hard globules of steel in the Cu of I came from the 4.5 to 8.5 Fe which the bands picked up from the projectile during welding. These hard spots would increase gun wear. Range firing results of I and II were about equal. Bore and flight-safety tests on I fired from new and old guns were satisfactory.
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