BACKGROUND: The MK III helmet was designed due to the lack of protection from horizontal projectiles offered by the MK II helmet. Experimentation was done with reshaping the MK II to offer better protection for the temple and back neck areas and while the shape was deemed good the steel was weakened. The new pattern that resulted could be shaped out of the same size plate of manganese steel used in the MKII. Production began in 1943 using the existing MKII liner and was issued on a replacement basis, the exception being the 21st Army Group who were completely equipped for the Normandy invasion. The MK IV helmet was introduced in September 1944 and was a modification of the MKIII which added a liner that could be removed without tools which was attached to a permanent stud by means of a lift-the-dot fastener. With no hole in the shell it could be used as a basin to carry water. The helmet was designed to be used in the Pacific Campaign after the war in Europe ended.

PHYSICAL DESCRIPTION: Constructed entirely of non-magnetic manganese steel, this pot shaped helmet, with an uneven all-round visor, retains 80% of its rough textured olive-drab paint. A separate stainless steel rim, that is folded around the edge of the visor and spot welded at the back, exhibits expected edge wear. The helmet slopes up sharply from the front visor going over the pot shaped body and slopes down the back at a more gradual angle to a larger flare at the rear. The visor slopes down at the sides to allow better protection for the temple and ear areas. Faint, stamping to the interior at the rear of the helmet which most likely reads "BMB" (Briggs Motor Bodies Ltd), "D 71", "45", "MK 4". The MK III pattern liner is the same as a MK II liner with the addition of a lift-the-dot fastener at is center. It includes a head harness of five tongues cut from a single piece of black patent leather, folded and stitched to each of their tapered ends to form tunnel loops for the adjusting drawstring to pass through. The head harness is stitched to the exterior of a horizontal black fibre headband, which has a black colored cloth covered rubber strip sewn to its interior, forming a padding between it and the inwardly-folded tongues of the head harness. The exterior of the headband has eight molded rubber buffers fixed between it and the interior surface of the helmet. Two black fibre crown strips are riveted to the horizontal headband and rise vertically, crossing one another to the interior apex of the helmet. A molded, cruciform shaped, rubber pad is fixed, along with the rest of the liner assembly, to the helmet through its central depression by a lift-the-dot fastener. The pad is partially missing. The liner band strapping is marked "BMB", "11" and the date "1945". The liner has stiffened and dried with age. The chinstrap is a MK IV strap that was introduced for use on the MK IV steel helmet and was designed for easy removal. The chinstrap has tears. The helmet is in good condition with moderate surface spotting and dust buildup to the interior.