I don''t know about 1953, but the old cordite "powder" came in long sticks, like miniature spaghetti. It was loaded into the primed case and a cardboard wad put on top before the case was necked down and the bullet inserted. AFAIK, that system was used only by the British. They claimed that the cardboard wad reduced throat erosion by some means that has never been clear to me.
I thought by 1953 they were using normal nitrocellulose powder, but I could be wrong on that. Or they could have continued that loading procedure even with regular powder.