Gee, thanks David. You should know me better than that. Remember the TSA days and when you bought your WC AR and we went out to the ERML range one day?
You are right in a way. With as many ARs as I have (34), it is hard to shoot many of them regularly. I do try to rotate their range visits, but I do have some favorites.
Honestly the only real upgrade you have on your list is the aimpoint PRO. The addition of any RDS is a huge improvement over irons.
KAC RAS:
As F2S stated this rail system is WAY outdated. If you are looking to keep the std. barrel nut then you can look at the centurion arms rail.If not there many good rails that are too numerous to list.
Troy BUIS:
This was a great BUIS 7 years ago, I used to run them I also broke them. The magpul MBUS offers the same thing at with lighter weight and a cheaper price. If you want metal look at the magpul pro or the KAC micro for top of the line irons.
Battlecomp:
As many have stated the battlecomp has a downward push that many dont like. There are many offerings now that offer neutral compensation.
I’m a big fan of free float handguards and if I could afford it, I would fit them on all my ARs. For those I needed affordable handguards for, I turned to Magpul and the best bang for the buck on your 6920 is going to be the Magpul Slimline. They are about $30 and are two or three inches longer than the round style to give you more room for your support hand. They are pretty light and don’t have any rails you don’t need and it’s easy to mount stuff to them, either by using an M-Lok adapter or fabbing something up on your own. You could go with a railed handguard, but what are you gonna do with all that rail estate you paid extra for? Metal handguards get hot. The Slimline does a good job of protecting your hands from the hot barrel and gas block, just like a handguard is supposed to. Currently, Slimlines are only made for carbine length gas systems but that’s what your 6920 is. Downside is the front sling ring will need to be removed and maybe the bayonet lug will need to be ground off to fit them.
Here is what the Slimline handguard looks like on my Wolf Pup. This shorty AR uses an low profile gas block instead of an FSB
I also love my Battlecomp. The 16 inch carbine it’s mounted on shoots smoother and with less muzzle rise with it than it does without it. Side concussion is a bit more than from an A2 but to me, the concussion feels softer. It’s MUCH better than standing next to that joker with a full on muzzle brake! However, I suggest you keep shooting that A2 birdcage for now. It works well as a flash suppressor. Pull it off and try a bare muzzle- you’ll see a big difference! But the bottom line is it’s more important to get to know your rifle than it is to have a fancy muzzle device. It’s also better to get your rifle’s system balanced by getting it set up with the proper buffer/spring combo before even thinking of a different muzzle device- and going with the A5 RE assembly will give you the best foundation to start with.
Get an RDS. Do Not Pass Go, Do Not Collect $200, Do Not Buy Something Cheap- Go Straight to Aimpoint and Get a Pro or spend a bit more for a Micro. (Pros are great and give you a lot of performance and is Aimpoint’s entry price model, but I’m glad I went with the Micro instead. I have to admit it’s an H2 and I got it on sale at a price that left me kicking my backside that I didn’t buy at least one more, but my next Aimpoint will again be a Micro.)
Next, get a sling. Simplest thing to do is get a long two point and set it up in the modern style
Top it off with a weapon light. There are many ways to mount a light to your AR. Here’s how I did mine
As you can see, you don’t really need much rail estate
Skip the PRO. Too heavy for no reason. Find a micro T1/H1 and put it in a light fixed mount. Eotechs, fullsize Aimpoints imo are obsolete until the weight comes down. I’m sure this is not a popular opinion, but been there done that. 12-14oz optics are not for me.
Also, with the introduction of the T2, there will be plenty of lightly used T1s coming up for sale.
At last, someone said it! I too have wondered why so much mass for producing a small red dot in Aimpoint Pro.
My evil plan, in a nutshell. 
As well as the H2 that they just announced.
I have a Pro and H1, not sure which I prefer. The larger window on the pro is a +
I don’t know… I’m of the belief that if you’re even seeing “a window” or the optic at all you might not be focusing correctly, or the optic is pushed too far away (I personally think most people’s are). I see nothing but a dot when the gun comes up. I don’t see a dot through a window with a specific eye, it’s just dot floating around.
As to the H2… The reps at SHOT were VERY FIRM that there would be no H2, there was no need, only a T2. I remember thinking it was lucky they had the couple of good products they have because they were not impressive at SHOT, nothing new for years now. The T2 is a nice revision, but hardly “new”.
They’re going to be in for a shock when someone finally ups the game on them. In the meantime… H1-used sounds like a solid ass buy!
For HD next steps are RDS and light. Anything else is gravy. I’m impressed you actually followed the ammo and training advice, very few people do that! Now you know why everyone advises training, but it is hard to see the value before you have had it. I had a leg up when I got into ARs as Uncle Sam gave me lots of training…but I still pay for, and go to, classes on my own when I can.
As everyone has said, you bought a good gun, and at the heart of things, that is what matters. Upgrades take time and more experience with to find out what suits you. I didn’t like the Battle Comp so I went with the BCM Mod 0 which was new at the time and I still really like it, but it took some understanding of what I wanted my rifle to do. The Military training I had was okay at best to the classes I learned latter, having said that, I learned from people with a lot of practical experience on what they thought their gear could improve on. This is extremely valuable to shape your needs and environment. Remember that if this is your defensive rifle, what environment do you see it lending itself to. Is it a Ranch type you keep with you on large open acreage, or is this a home defense rifle in the heart of a major city? This understanding will help shape what you need, and why. Stay the course and make some mistakes, so long as you learn from them you’ll be just fine.
I set my first Colt up almost exactly how you described, Aimpoint, blem RAS rail, vfg, and a Surefire. If I did it again I would choose a lighter rail/handguard, the KAC RAS is great but it adds a lot of weight. If you’re not looking to spend a whole lot but want to set up a vfg and a light, I would recommend the Magpul MOE handguard which is a much lighter, cheaper option.
I think the Aimpoint Pro is a great choice, I like it better than my T1! You should be able to find one for under $400, I got mine from Primary Arms.
If it were me, I’d stick with a skinny carbine handguards and put an x300u on a mossie midnight mount. Skip the battlecomp. If you must upgrade, my advice would be a PWS triad.
Interesting, never had the 2 side by side, but I always the BC and KAC TT were similar in performance.
I would skip the Battlecomp. There are quite a few muzzle devices out there now that do all of what Battlecomp does, better, and is less concussive doing it.
I liked that range. The black bucket thing they had at the 100 yard berm was fun to shoot. Of course that was a long ass drive for me to get there!
In my opinion and in my hands, the TTT out performs the BC.