OPBN-
I purposely did not use any kind of glue to attach the CF tube to the remainder of the bodies. The CF tube slips on with a very slight press fit instead. I did this in case, for whatever reason, the CF tube cracked, or was crushed under misuse - the user could simply pull off the old one and press on a new sleeve. I would not recommend using any kind of glue or epoxy on the interface for this reason.
I'm not sure how exactly the new tube could differ from one I've done in the past because I've always used the same dimensions. The sear slot and on/off pin are scaled down a bit from a ULE body, but have worked great in all of my testing and for many other users. Could you get a picture of the slot and holes from the two different sleeves side by side so I can see whats going on with them?