.303" Cannelure Wax?


#1

British govt publications ,“Textbook of Smallarms 1929” and “Textbook of Ammunition 1944” state that the cannellure on .303" bullets was filled with beeswax. Late production ,post 1945, lacks the large cannellure towards the base and seems to have a black sealant.
When was the official change from beeswax done?