I've found it hard to justify spending that many points for Gant shooting. I've seen some people who use that combo and it doesn't seem to be worth it most of the time. Typically, IMO, Tyranids are best off when they stick together and come in as a coordinated whole. That's not to say reserve lists don't work, I'd just rather drop three Trygons in my opponents face with Hive Guard, Zoanthropes, and two troops Tervigons as backup.