Does that AR15 have enough room for the bolt to travel?

Also that's a really bad place to put the mag release on a bullpup since it means you'll have to take your right hand off the grip to press it rather than reloading with your left.

In fact, better question: How is the bolt actuated in the first place? Since there doesn't seem to be a charging handle of any sort.

I'm not really sure myself but the rifle does look like an M16 M17 Hybrid. Unfortunatly I haven't spent any real Quality time with the Bushmaster M17.

Could (and should) be on the left-hand side of the foregrip like the TAR-21 and AUG, in which case you wouldn't be able to see it unless it stuck up diagonally. Though that would make the right-hand-side mag release even worse.

Something I threw together that just clicked for me.

http://i294.photobucket.com/albums/m...0Gun/G36A3.jpg

If you put in a magazine it'll do more than just click. http://img.photobucket.com/albums/v4...mot-eng101.gif

I do most of my builds without mags to give them a "gun rack" look.

Something I just made up. Nothing special really

http://i71.photobucket.com/albums/i1...yweapon-21.jpg

You forgot to take the original handguard off before you added the RIS.