Casting happened today. Much of it. But first, here's a pic of the various mold chunks that go into making the Battle Rifle parts:

In the background you can see the molds for (from left to right) the scope, the small detail bits, and the barrel assembly. That chunk of rubber sitting between the rifle mold halves on the far end is the plug that separates the rails.
I failed to mention it before, but I decided I wanted the trigger guard to be a bit more sturdy than a thin piece of casting resin. So for each casting I'm inserting an aluminum triggerguard which gets cast into the final piece:
Here's a shot of the second casting coming out of the mold:
Here's some sort of maniac holding the first two castings:

The one on the right is the first casting. I made it with some cheaper resin intending it to be a throwaway cast (to get the last bits of clay and whatnot out of the mold) but it came out good enough that I'll go ahead and finish it.
Here's a closeup of the aluminum trigger guard:
Here's the prototype with the first set of detail bits added on:
The castings have very few bubbles. Here you can see a few of them near the magazine release:

With so few bubbles, cleanup and filling should be minimal.
The molds aren't quite as tight as I'd like, so there's a lot of mold flashing. The worst of it is around the butt end and grip:

Still, it will only take a few minutes with a file to cleanup the whole thing.
So at the end of the day, here's the prototype and the first two sets of castings:
Stay tuned for the next step...
PAINTING!
Meanwhile, please feel free to leave a comment. This thread gets no love.