One of the nice things about the MI mount in that setup is that the screw head is under the light. So, even if the screw starts to back out and get loose, you’re not going to dump you light on the deck and lose it forever.
I go back and forth, but the Troy sight is lighter than the Larue, and may well replace the Larue on this gun eventually. I don’t know the A2 vs. flattop/T-1/Larue weight.
Is that a single point sling you’re running? I would need to knock the sling mount off the FSB on my 6920 to get a light mount on. I’m thinking of going to a single point because of that (and I also have no rails).
Nice. I may have to pick one up.
I bought the 6520 for a lightweight teaching gun for my daughters, and for hiking or carrying on my ATV. I resisted the urge initially to tart it up, but since I bought it, Aimpoint released the T1 and SF released the X300. Both of those things kind of negate the weight penalty you pay for a fully capable rifle.
I’ve tried single point slings with the AR-15 and I think that the single point just sucks for that purpose. Sure it does “work” in a way but it allows the weapon to move around too much when you let it hang. Though I do like the single point sling for off hand transfers. I too have a Colt LE 6920 and I removed the sling adapter from the barrel. It wasn’t exactly difficult to do either. I took mine off because I didn’t plan to use it with any sling I decided on and because I didn’t like the sling thing flopping around while I was using the weapon. Just something to think about.
Let me guess, the sharks are extra though? 
Someone suggested placing this thing
http://www.blueforcegear.com/product.cfm?type=cat&cat_id=5&prod_id=81
at the delta ring and going with the two point sling.
Yeah I’ve seen those. I’m not a big fan of the design for most applications. I’m going to get the sling quick mount attachment from Daniel Defense and use one of the quick sling points on the Vltor E-Mod Stock. I ordered a VCAS sling for mine.
I have a rifle set up that way but haven’t run it yet.
Are you using the shorter or longer of the two?
I actually prefer standard handguards over rails and its not because I can’t afford them. I’m just old school when it comes to ARs. I like the traditional look and feel of the standard configurations (iron sights only, etc.). I have two M4 clones and an M16A4 clone, and of those, only one has an attachment on it (flashlight mounted on a single GG&G strip).
That said, I do plan to put a free-float Daniel Defense 12" on my next build (another 20" bbl M16A4), but only for the sake of accuracy. The only attachment will be a Harris bipod.
I have found, as have most of my peers, that a free float setup is essential when combining receiver mounted optics and a 2 or 3 point sling. (This clearly manifests itself when using a longer and/or lighter profile barrel. ) I have not tested this with a shorter and/or heavier weight barrel.
Shorter.
I claim no greater wisdom or experience than anyone else, but I do not believe iron sights are so inferior that RDSs are not optional but mandatory. As I said, a light is mandatory, but a RDS does not rise to the level of mandatory in my opinion - nice to have, but not ALWAYS the best option for HD or CQB.
I used irons exclusively during many years for Uncle. I saw action at I-can-see-facial-expression distances. I was Sr. FI for several years for a gubmint agency that fielded M16s. I have ARs with irons and Eotechs. I have experience with Aimpoints and Trijicons. I like RDSs very much. I do not feel they are mandatory. Last time I attended Select Fire Instructor class, I shot irons only and had a really big time.
So you feel the bell has tolled for irons?
BTW, I saw your excellent article- nice work!
I see your point re: necessary vs. nice to have.
I’m looking at it from my end and my non-professional use, and the shooters that I observe. Get an RDS on the gun, get them focusing on the target instead of the dot, and hits and speed just seem to increase to the point that “necessary” may be a bit strong of a word, but not far off.
I have a kid that works for me that was a Combat Engineer and got out 5 years ago +/-. In his 3-4 years in he NEVER fired a rifle without an RDS. Obviously not “necessary”, but it seems that even the so called “Big Army” is putting an awful lot of faith in them.
So, while I wouldn’t say that the bell has tolled, exactly, I don’t see the shortcomings in quality RDS that would lead one to still rely on irons for the majority of users. Obviously things outside my lane like going house to house in Iraq notwithstanding.
thanks, on the article. Hopefully the second of more to come. 
Good points made here.
In 2003 in Iraq we had a heck of a time getting things other than absolute combat necessities fixed as the higher level support infrastructure in Iraq was in it’s infancy or simply non-existent. In the course of the many “cordon and knocks” or “raids” executed with my M4, my M68 went hard tits up. Some prism or reflector got jarred out of place in the tube and rendered the optic useless. I removed the optic and BUIS from the weapon (truth be told I hated the Matech BUIS we had) and ran just the good old A2 charging handle with my Surefire M951 and some orange paint on my front site post. I ran this setup for quite some time, and it served me well for many patrols, 2 full blown fire fights, and countless dynamic entries. Would I have preferred having my M68? Absolutely. Was it a necessity to successfully completing my duties as a rifleman and team leader? Nope.
I, too, wouldn’t go so far as to say an RDS is mandatory. But I think the evolution of the sights has put to bed most of the reasons for not having them. Aimpoint killed the battery question with some of their new sights. Leave the sight on and change the batteries out every summer Olympics or 5 year anniversary. Weight and/or bulk? Check out the micro Aimpoints. I think the only reasonable barrier still remaining is cost.
While irons are still viable, I think the reasons to stick with them are dwindling away. What they do for overall performance make them worth the minor tradeoffs required.
Back to the rails. Rails are not required, but they sure do make things easier. Lights, slings, VFGs etc. are all easier to mount on a rail. The other nice thing is that they let you try things out and experiment to see what works best for you. You can screw a piece of rail onto a handguard to mount a light, but you may decide you don’t like it there. Then you have to drill more holes. You can move the VFG fore and aft until you got it where you like it.
But if you know what you want and where you want to put it, you can get away without rails. You could even get one of the Surefire fore end lights that replace the handguards. They feel like standard handguards and get you a great light. But if you want to stick with the regular hand guards, there are piceces of rail and mounts that let you put stuff on without having to replace the handguards.
I think that most people would agree that (outside of training, ammo, mags) the order should go something like:
Thanks, all, for the informative discussion. I basically want four things mounted on the rifle: an optic, a light, BUIS, and possibly a bipod for special occasions. One of the things that appeals to me about the rails is the number of options for flip-up front sights. I’ve not yet gotten to try sighting through an optic on a rifle with a fixed front sight to find out if it causes me a focus problem… I’ve heard some say it’s no issue and others that they can’t stand it. If I feel I need the flip sight, I’d just as soon go ahead and get a rifle with no fixed FSB and rail-mount a set of Troys or similar. The current contenders are, assuming eventual availability:
With rails:
Noveske N4 Light Recce Low-Profile (how much $$$ for these, anyway?)
LMT CQB MRP Defender 16" (and swap out the standard sights)
Without rails:
CMMG Mid-length MedCon (with upgraded BCG)
Noveske N4 Light Recce Basic
I’m looking at complete rifles because although I could probably spec out a Franken-gun for a little less, I’d have to pay someone the difference to put it together for me anyway. I know I could add rails later to one that didn’t come with them, but it doesn’t seem to be significantly cheaper to do that, even were I to use bolt-on rails.
Am I thinking straight?
As an arrow. If I don’t succomb to SCAR fever, my next AR will include rails with flip up sights. My short list is:
LMT MRP Piston
N4 Recce
KAC SR15 E3 IWS
I’ve shot a couple of ARs with magnified optics and fixed front sights and it seemed fine to me. Other users have way more experience and could give you better input.
Like I said, the main benefit to me of the rails is the versatility. You can clip stuff off and on as you see fit, and move it around. With standard handguards, that versatility is reduced. I like the rails, but you could build up a slick set up without them if you choose. Your options are more limited, but it can be done.
IMHO if the front sight base is causing you issues, you’re doing something wrong.