The worlds biggest machinegun.
Burst rate of fire was a whopping 14rds in 45sek
Its "real" designation is
bandkanonvagn 1, or
bkan 1 for short (models ranging from A to C)
Only drawbacks, they cost an arm and a leg and weighed a ton (well, 53 metric tons actually...).
Pretty impressive for a sixties design IMO.
http://www.pansarmuseet.se/bkan1.htm