Gee, Perry, sorry about that...NOT :-)! Here's a thought, rather than buy another gun and tune your CFX, kill two birds with one rifle and get a gas ram! Sorry, guys, don't want to hijack Perry's post, but I've got some impressive numbers to post elsewhere, so I'm kind of psyched right now.
Perry, I'd leave that ridge alone. It acts as sort of a bearing for the front of the rotary. There's a matching ridge around the back of the rotary as well. Considering the headaches I've had with mine, if you don't need to remove it, DON'T! However, if you choose to ignore my impeccable advice :-), I'd like to know if the rear seal is anything other than a simple o-ring. The most recent exploded diagram I've been able to find shows that seal as more rectangular in cross section. If so, it probably seals better than mine. HTH.
Dave