Chris : heres a link from the 1/35th site , there may be a few 54cm pics on it , the karl morters barrels were interchangable,( between the 54 and 60 cm) if I am not correct , they only lasted around 60 to 70 shots anyways then were discarded , ( they just got worn out from the shell weight I suppose )anyways heres the link , I hope it helps a bit ! http://www.one35th.com/morser/karl_main.htm