URX II Question

to the urx users,
i have a colt govt carbine with the .625 barrel that i am going to put a flat top upper in place of the carry handle upper and would like to put a mid or rifle length urx 2 rail on it. if i have the fsb shaved down would this be possible? i know the newer versions have been modified to make this easier but i have not had much sucess finding one. is the newer version my only option or with the shaved fsb would one of the other versions work? thanks,Mike

Why not get yourself something like this & add a gas block, You could sell off the Colt lightweight barrel & recoup some $$$

http://m4carbine.net/showthread.php?t=45874

that is a thought that i had considered. if i do that i will probably go with the centurion lightweight hammer forged barrrel. can get it with a gas block already pinned and mid length as well. from all my research it seems there is an issue with the older versions of the urx in fitting a low profile gas block under them so i thought shaving the fsb would be an option for fitting the rail.Mike