here is a parts diagram for the 550
http://www.czub.cz/detail/images/cz550ro.jpg
and here is a cut away:
http://www.czub.cz/detail/images/cz550rea.jpg
what i cannot tell is if the 550 evolved from the 601
what about going with an ashley?
http://www.ashleyoutdoors.com/mounts.html
HTH
dZ
[This message has been edited by dZ (edited March 03, 2000).]