www.ar15.com is a fantastic sight that has great advise. Post a question and you will receive much feedback from folks who know their stuff.
Rock River makes a fantastic AR15 (and variants) at a very reasonble price. Bushmasters are nice but you pay much more for the name. RR lowers and barrels are the same manufacturers as the Bushmasters' (this is what I am told by some gunsmiths).
The AR15 is a good platform with many aftermarket accessories that you can use to customize you rifle to suit your needs.
Rock River is good, but chrome lined barrels aren't standard. That's one of those things you want to make sure you get (especially the chrome lined chamber for better feeding). It's standard on Armalite, Bushmaster, Colt, LMT, and a few others, but not RRA or Olympic. (But Rock River Arms M4 profile barrels are typically chrome lined). Also, if you want to be one of those high-speed operator types, you'll want to shoot 75 or 77 gr bullets, so you'll want a 1-in-7 twist in your barrel. And you want the M4 feed ramp cuts. And the correct height F-marked front sight base. And an MPI (Magnetic Particle Inspected) bolt carrier group. Apart from a few lesser-known manufacturers, that means you want Colt or LMT. And maybe CMT/Stag, but you have to make sure about what you're getting.
If you want to be a super-high-speed operator like me (I've seen Red Dawn and Heat like three dozen times), you might want to loiok into the Leiter-Wise pisaton-driven system, but the wait on those is pretty interminable (I'm still waiting on a rifle ordered back in February or something). Or for a lot less money, a midlength system (which is reputed to give much better reliability that a carbine-length gas system).
Unless you care about collector value (in which case you should not buy anything but a Colt), I'd buy a stripped lower, a lower parts kit, a cool telescoping stock like a LMT SOPMOD or a VLTOR, and a complete upper. All stripped lowers are pretty much created equal, so I'd buy those based on price and how much you like the logo. For the upper, I recommend
Bravo Company for uppers. They have a good selection of top quality stuff at reasonable prices.
Damn. I think I might have spent too much time on ARFCOM (before I got banned for gettin' stinkin' drunk and expressing some opinions that proved unpopular with one of their mods).
