Canada purchased 40,000 long Lee service rifles in 1896. They served well through the turn of the century. 10,000 were sold off surplus to New Zealand just before WWI. Many of these years later ended up on the world surplus market to be imported back into Canada.
Canadian marked rifles sometimes have markings that suggest an interesting history. That is a Canadian Sold out of Service marking over the top of the standard Enfield rifling barrel mark.
There are some variations on Cdn SoS markings used, this is a new one to me. Surplussed Canadian rifles generally as a rule, do not get the SoS markings unless there is a reason. Not saying that this is anything special, but it would be interesting to find out what you have there.