Scott makes good stuff. First choice for firefighters among most others needing quality optical protection. The compatibility with NBC canisters is a big bonus.
To muddywaterman, Nice pick! I'm a fan of the 20" over the carbine or 10.5" barrels as it takes best advantage of the .223's capabilities. Stagg used to make the lowers but I've heard they've moved mfg in house now. Just a word of advice before you hang a christmas tree on the front end, every pound counts! The more weight you throw on the front is going to cause fatigue to set it sooner and that means a loss in accuracy.
As far as optics go, I personally had a few different handle mounted scope mounts and they are not all created equal. I had problems with several of them shooting loose. A 'quick fix' is to use a small viton 0-ring between the bottom of the handle and the top of the screw where they meet. It will still shoot loose but you'll make it through a few clips before you have to finger tighten it again. I tried different plastic and rubber washers as gaskets but they all deformed too quickly to do much good. For a scope, I had great luck with a 'cheap-o' Simmons Whitetail classic. I could shoot bug holes at 100yds with it and it never lost zero after I figured out the o-ring solution on the 'picatinny' handle mount.
Also, just in case you didn't already know, the AR-15 likes a wet bolt and carrier. Wetter (with oil) than I'd ever normally oil a gun in fact. I tried graphite and other high viscosity oils with a lighter coating and paid for it with obnoxious amounts of carbon build up on the bolt/carrier. If I 'soaked' it in
rem-oil, it shot w/o malfunction with much easier (though still excessive in my book) clean-up after each session.
Hope all that ^ helps you with yours. Another add on to look for is called an 'accu wedge' that fits into the lower behind the rear take down pin. Keeps all the slop and flex away and really help keep the rifle tight. Like I said, I was shooting bug holes at 100 yds with a 20" upper with a CAR stock...
DPMS Accurizing Wedge AR-15 - MidwayUSA
best $5 you can spend for your AR!!!