Another gun on permanent display at the Armories of the The Brockville Rifles:
My copy of Ian Hogg's Twentieth Century Artillery (Etobicoke, Ontario: Prospero Books, 2000) identifies this as a 77mm Field Gun M96nA. This was the principle German field gun at the outbreak of World War I, and it featured a hydro-spring recoil system and Krupp sliding breech block. Interestingly, Allied combatant nations of the time used field guns with 75mm or 76.2 mm, so Krupp made this gun 77mm in order to ensure that it could not be used with allied ammunition if captured. (In contrast, if the Germans captured Allied field guns, they could bore them out to accept the bigger German shells.)
Below, detail shots:
A nice touch is the beautiful decorative engraving on the barrel!