Use structural support near the base of the barrel. Also, glue the barrel(s) on with just a little bit of hot glue before you use something more powerful and with a longer dry time. That way it will be somewhat stable while the power glue does it's job.
Awesome news. The Firefly sounds freakin' awesome, can't wait for some pictures and info. I doubt they'll re-release the SM line - they practically just did with the Air Tech guns. I think they'll go back to the Air Jet guns (Powerclip, Blastfire, Splitfire, SS2). That would be huge. But I dunno about the old-school guns....here's hoping for a new and improved B'n'A.