Hmm, my bad got my terminology mixed up :P
dagda, check inside your hopup unit. make sure the brass ring isn't inside still. other than that, just use a little more silly oil on the outside of the hopup rubber/sleeve and work it in slowly.
Ahah! I had been wondering about that ring! So it is supposed to come out? Is there any way in which I'm supposed to go around removing it? Tried prying at it with a screw driver for a while to no avail.
Edit: V! Got the ring off, just took a scary amount of force, thank you. Now what am I supposed to do with the ring? Put it on the barrel before the rubber so that it ends up where it started?