@David-DJD : The Medicine Hat CPR Depot hammer is listed with a rarity factor of "C", meaning it was in use for 11-15 years (Using the bnaps RPO cancellations catalogue, their RF goes from "A", more than 25 years of use, to "G", less than 1 year of use). Yours is the state 1 of this hammer, with a ERD - LRD of 1918/03/04 - 1930/05/04
I was having a great time browsing through this topic and decided to give it a try.
Winnipeg, Canada, JUL 21 44

Edmonton, Alta. OC 15 43

The Fathers of Confederation cancelled at Unity (

), Sask. DE 6 17

The scan doesn't do it justice because I can clearly make out Saanichton, BC, 3 XI 56 with my own eyes

Windsor, Ont. Jul 18 41

Toronto, Ont. S.O. 117, Aug 26 38

Brockville, Ont. Ju 10 98

Jonquière, PQ, Nov 26 34, my father's hometown

Toronto, Ont. Oc 16 33
The lower part of the cancel I can't make out or understand it's meaning. As far as I can guess, it's "REG. DIV." and then quite a few letters I can't discern

Montreal, PQ, Aug 9, 5:30 PM, 1921

Speaking of out of period cancels, here's a WWI War Tax stamp cancelled during the WWII

Winnipeg, Canada, Jan 27 42

Ottawa, Canada, Jul 2 06

And last, a two ring numeral from Kingston, Upper Canada (#18)
