That's a gorgeous base for a blaster rifle though! I can definitely see a sleek little carbine or sniper rifle built out of that 
I'm planning to go the carbine route. I've been reading a lot on the electronics board and watching a bunch of youtube LED vids. I think I'm a touch overwhelmed at all the possibilities for light and sound but I should have some time to draw tonight.
If you mean the bore, well, I'd expect something square coming out from a square barrel. Don't know if it makes sense.
I did mean an opening to represent a square "bore." Since it's a blaster and not a slug thrower I wasn't too concerned with the idea of the shape of the projectile. I assumed plasma would take whatever shape it feels like taking in transit (if that's what blasters project) and I'd guess light is a lot like water in filling the available space (if that's what blasters project instead.).
Now that I have the line drawing to print out and draw over I can get some sketches done. Hopefully I add them here later tonight.***edit/addition (3/7)***
I'm not sure where it's coming from, but I like the rounded profiles. Each drawing has a muzzle view as well.
The small circles on the sides of the muzzle (which would be the ends of the stock's forend) are plnaned to be integrated lights (rather than an external light) though I'm thinking of making it look like a light panel on each side (cover the LEDs with a frosted plate or something.
Not really sure what the under muzzle hole will be In-universe but for right now it's the where I'm thinking about putting a speaker for blaster sounds because I'm not sure how well it would work to put the muzzle LEDs in front of a speaker... But those are problems for later (once I have some electronics experience), and another board.
