For the sharp-eye folk out there, yes, it is a half scale replica of the business end of a Avenger GAU-8 30mm gatling gun. The one on the A-10 Warthog.
I first it saw it on the Internets, somebody had printed it out as a quarter scale display piece. I though, "We should make it twice as big and use it as a brush holder!" As one does. It was a bit of a hunt to find the STL file so we could rescale it and print one for my very own.
The muzzle prints as one piece, no supports. Took nine hours, but the Prusa servitor did just fine by itself.
It was printed in black filament, but I wanted a bit of contrast to it. I found a picture of a GAU-8 sexed-up a bit for an airshow, so I went with that color scheme, not quite as shiny though.