Here are two hackbuts from Sweden:
http://www.historiska.se/data/?foremal=123316
With remains of the wooden shaft. Found in Skåne in the region of Norra Åsum, this one is undated. Barrel 101 cm, calibre 19 mm
http://www.historiska.se/data/?foremal=115866
Found in Stockholm, dated to the late middle ages. Barrel 106 cm, calibre not mentioned.