Minister of Militia and Colonel, Sam Hughes was the driving force behind Canada's mobilization in August 1914. He was what we would call a Type-A personality, but he made a lot of mistakes.
One of Hughes' more glaring ones was his insistence that the Canadian army carry the Ross rifle. The Ross was made in Canada, and Hughes was its natural champion. Superbly accurate, the Ross was used to win international shooting competitions, but it proved to be unreliable under battle conditions. That didn't deter Hughes, however, who had so much of his own personality invested in the Ross that it was impossible for him to back down, and he continued to champion it at all costs. Early photos of Canadian troopers show them sporting the Ross during training.
In spite of that, the Canadian Mounted Brigade, made up of the Royal Canadian Dragoons, Lord Strathcona's Horse (Royal Canadians), and the 2nd King Edward Horse, crossed the Channel in early 1915 and went into battle--carrying the British-made Lee Enfield Short Rifle. It was not the only time the cavalrymen broke away from Hughes' guidance.