As long as the buffer tube isn't too long or if you go with one of those newfangled ones with NO buffer tube, you should be good.

NO buffer tube? How does that work?

? I've seen short bcgs or uppers made with pistons that don't use a buffer tube.

Here is RRAs version.
http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=441
A neat idea not sure if I like it though.

Yeah I'd like a faxon upper

I guess I'll wait til I get it put together to see what sort of optic I'd want on it. I hate waiting.

Fairly sure I don't want to run a red dot, but still not sure if I want a rifle scope, compact rifle scope, or a pistol scope.

Trijicon accupoint
A base model aimpoint or eotech with a mid quality magnifier like a vortex would be awesome.

GD, you don't have a budget, do you

Actually, I have a 2MOA aimpoint with a Vortex magifier on my RRA for my "it all went south" gun.

I just dropped the cash on the Sig SB15 brace on eBay. Someone had 5 for sale. Offered at $110 with a "make an offer" price accepted for 100. Never saw a new one that low before....now how to explain ANY of this firearm to the wife...

Nikon Force XR pistol scope may be the way to go, but I won't know for a while til I can sell off a thing or two in the safe.

HA! I don't even have money to get ammo for it yet, let alone dies and components! 110 VMax or Barnes Black tip coppers. Should expand at relatively low velocities with decent enough penetration.... or so I hear. No testing for me probably until Christmas... if I can get a box or two of the Hornadies bu then.

So far I have or have on order:

--Pistol lower

--8.5" BLK upper

--M16 nickel boron BCG and charging handle

--plenty of mags

--Magpul AFG2 (since srtaight grips are illegal but not angle d ones....go figure)

-- Sig SB15 brace

--Venom 45 degree offset BUIS


Still missing:

-- scope

--scope mount

-- ammo

--dies

--components (only need brass and bullets)

-- compact green Ncstar APRLSMG laser just because I want a green laser on one of my guns and this seems the coolest one for it

Hahaha! Just when I thought I could do this project on the cheap! No such thing

What budget? lol I blew way over budget on my current build by like $400 or $500. But it's exactly what I wanted soooo who cares??? Lol

This is the way I always end up. LOL I should just up my budget but I am worried I would then over run the new higher one.

Lol right? That's what happened to me. But my rifle is totally over built