English: M109A4B 155-mm SP Howitzer, CFB Valcartier, Quebec. The M109 is an American-made self-propelled 155-mm Howitzer, first introduced in the early 1960s. 76 A4B+ were in use by the Canadian Forces from 1967 until they were phased out in 2005. In the 1980s of of these SP Howitzers were modernized to the M109A4B+ SPH standard. 24 of the M109s served with 4 Canadian Mechanized Brigade Group (4 CMBG) in Germany until 1992, with the remainder distributed to units in Canada, including CFB Shilo where more extensive and varied live fire exercises could be carried out than those conducted by 1 RCHA at Grafenwoehr and Munster in Germany