Ammunition Shelf Life
Within the Canadian Forces gun, howitzer, and mortar ammunition does not have a service or shelf life. Service life and shelf life are assigned to certain items such as pyrotechnics used in survival kits (flares, smoke pots, etc) and Cartridge Actuated Devices used in aircraft safety systems.
Depending on the type of ammunition (gun, mortar, howitzer, small arms, etc) and in some cases the type of packaging, location and storage conditions there is a set inspection interval to verify the servicibility of the ammunition. In addition propellant samples may be removed for additional testing to ensure there has not been any deterioration of the propellant. Additional proof and test of the ammunition can occur if the ammunition shows signs of deterioration or is suspect for any reason.
The user units can also submit ammunition defect reports if they feel that the ammunition is not functioning correctly or within set tolerances. These unit generated reports could also lead to a special proof or test of an ammunition item.
I would not consider artillery ammunition from 1985 old. I am sure that if you dug deep in the storage facilities of most armies you would find ammunition much older than that and it would still be serviceable.