The M109A4 was purchased by the Canadian Army to mostly fulfill their NATO mandate in Germany. After the withdrawal of CF troops from Lahr and Baden-Baden in the 1990s, the Regular Force Artillery units were equipped with them until their retirement in 2005. If my memory does not fail me, this particular gun, serial 85-78225, was in use by 1st Regiment Royal Canadian Horse Artillery in CFB Shilo, MB. I had the privilege to serve with this unit from 2001 to 2003. This was a great unit to work with and we had a blast. If you are interested, on some characteristics of the howitzer, there is plenty of information available online.
The cache is a camouflaged matchstick container. There are numerous hiding spots however this should be fairly easy. Enjoy the hunt.