If you hold down zoom, it keeps the barrel spinning, but it doesn't fire, so when you do engage, you don't have to bother with the long startup time.

I heard people say they were expecting that pre-release, but it wasn't confirmed at the time.

Good to know it does work (not that I play Heavy, but it's still nice to have someone verifying it)

I have mixed success with the minigun - It seems to work best when firing in small bursts? How unusual for a chaingun!