This article is from the can.talk.guns FAQ, by Skeeter Abell-Smith email@example.com with numerous contributions by others.
C-51 came after C-83 which was withdrawn by the Liberals and then
justice minister Ron Basford. Among other things, Bill C-51 created the
FAC (Firearms Acquisition Certificate) and prohibited fully automatic
firearms (unless registered before January 1, 1978).