From Concise Lineages of the Canadian Army 1855 - DATE (i.e., 1982), by Charles H. Stewart:
6th Machine Gun Battalion, Canadian Machine Gun Corps (organized 1919)
6th Duke of Connaught's Royal Canadian Hussars (name as of Aug 1892)
Have you also considered the possibility that it is the "6TH" Company of a Regiment.
AJFitzpatrick - if you follow the lineages of various regiments, you can find periods where the unit name switched between "Battalion" and "Regiment" without necessarily including a change in organization or size.