This is an original WWI British manufactured MK. I helmet that was converted to an M1917A1 by the United States government during a reconditioning process that first began in 1936, prior to McCord's new production line of 1941 manufactured M1917A1 helmets. The helmet's exterior features original U.S.-applied olive drab paint and cork texture. The helmet's interior brim is marked "BURYS D/O 22", denoting steel supplied by the Bedfurd, Burys & Co. of Sheffield, England. It retains its original leather liner and khaki chinstrap. The chinstrap exhibits the early cast brass buckle and box stitching, while the liner retains its original leather drawstring and crown pad. During the conversion task, British helmets would often have their split chinstrap rivets swapped out for the domed U.S. style, as evident on this example. The M1917A1 was seen atop the heads of Marines fighting on Wake Island, Bataan, and even during the early days of Guadalcanal.
Pre-WWII Converted M1917A1 Helmet (MK. I British Shell)