I swapped out the 12.5" Kino with an 11.5" SOLGW barrel. I also swapped out the ACOG for an Aimpoint T1.
Why I swapped out the ACOG for the T1:
See this thread on shooting in the rain: http://www.m4carbine.net/showthread....-case-for-KISS
The ACOG is a robust optic. I am a huge fan of them, but I can run a T1 much better. Good enough in any realistic scenario that the magnification of an ACOG (it's only benefit over a T1) does not outweigh its negatives. It's heavy, the eye relief isn't very good which coupled with suppressed use equals an eye that burns frequently, and the low light performance ranges from mediocre to absolutely poor if shooting from darkness into a lighted area. The T1 has none of these issues. While my cheekweld is pretty similar with the T1, the eyebox isn't so particular and you can work around it a bit better. I now run my ACOG on a 10.5" LMT as a beater gun for the woods.
Using the T1 led to the 11.5" swap. With the weight savings of the T1 and the lack of 4x mag I felt there was no downside to go a bit shorter and lighter on the rifle as well. It was just added weight, and having a PEQ and light so much further far out on the weapon made it pretty cumbersome even with the suppressor off. With the suppressor on it was lethargic to get on target at best. The 11.5" and carbine length rail coupled with the T1 swap made a huge difference. It went from basically feeling like a 16" Carbine to an SBR. The rail is 2" shorter, the barrel is 1" shorter, and now the accessories are about 2.5" closer to the balance point of the rifle. I didn't bother weighing anything, but it is a much handier rifle now and faster to get on target.
I also added a Gemtech Suppressed BC to this rifle. The main reason I got it was to reduce gas in my eyes when shooting suppressed (especially in humid/rainy conditions) and to be frank it hasn't really worked. However, the rifle does run much more smoothly with it in on the suppressed setting and I haven't encountered any malfunctions with it whatsoever.
Everything below that is not mentioned above still applies.
Original post as of 7/11/2016
The below rifle is a result of professional and amateur day/night experience. For several years I thought a "do all" rifle just wasn't possible. You can be the jack of all trades, but the master of none. A rifle that shoots well at 600 yards is never going to be fast and agile in a shoot house. This is still true, but I feel this rifle mitigates the disadvantages both sides of that spectrum.
Optic: For a while I thought this do-all rifle formula started with an Aimpoint T1. It's light, durable, reliable, and retains zero. While it absolutely excels in the role of a <300m carbine, much of my training was centered around the ACOG and frankly, I just enjoy shooting out to 600 yards too much. This is absolutely possible with a T1 but you're esentially holding up in the air just guessing where your rounds will go. Even with a magnifier you don't get any better at long range because you have no way to make accurate holds. Given my desire to shoot well further out, I sacrificed some close-up speed for more all-round capability and got a TA31RCOM4 ACOG in a GDI QD mount. While a T1 is certainly faster at <25 yards, the ACOG isn't terrible.
Upper: The upper is a 12.5" BCM Kino upper with the FSB at the mid length position and a Centurion 11.5" FSB cut out rail. This rail allows me to mount a light and an IR laser next to the FSB and still have approximately 9" of rail for a decent grip. To date this is the best system I have found for IR laser use. While other platforms work, there are many drawbacks. Shorter rails do not have enough space to get your support hand further down the barrel to provide muzzle climb reduction because there is always a laser or a light in the way. Keymod/Mlok rails introduce a potential (albeit small) failure point by requiring add on parts for picatinny rail mounted lasers, and they tend to be thinner which gets crowded when mounting a laser, flashlight, and back up front sight.
I went the 12.5" barrel route because it provides the best blend of velocity with maneuverability, especially suppressed. I also went the kino route because I love forged steel front sight bases. Many people find iron sights to be a relic of the 1960s, but I have never picked up a rifle that was previously zeroed with iron sights and been unable to hit the target. They work. I also chose an AAC 51T Flash Hider. Brakes of any type are loud. I felt the 12.5" was long enough to give some protection to the suppressor, and could go without a sacrificial blast baffle.
Accessories: I hate tape switches. The wires get in the way and I always worry I am going to rip them out of the gun when presenting the rifle too quickly. However, without a tape switch there is no easy, comfortable way to present the rifle and activate the laser and light. I have big hands and I was able to get my support thumb on top of a PEQ/DBAL on top of a KMR, but the issue then became when shooting normally (99% of the time) your thumb has nowhere to go because there's a huge IR laser in the way. Using a tape switch allows me to shoot with a c-clamp grip comfortably yet still activate the laser or Surefire M300 in the blink of an eye. I have it set up so that my thumb rests naturally on the IR laser as an IR laser ND is much safer than a WL ND. Larue makes a great set of rail covers and conveniently included are methods to retain tape switch cables. This solved the fragile, in the way, tape switch wire problem.
I am a huge fan of the Steiner DBAL 9007 - it is $780 delivered all over the internet and has a fantastic IR Illum with QD and a small footprint. However, I prefer the PEQ for several reasons for this build. The first is that the tape switch worked better with it. The tape switch was critical to this rifle's function. The second is that the PEQ sits lower to the bore than the DBAL. When mounting a flashlight and a laser on opposite sides of the rifle, I wanted to tuck things in as much as possible. The third is that without a T1 to cowitness a PVS14 (thus making zeroing an IR laser a snap) I felt a visible laser would be useful to confirm zero quickly and at similar price points I prefer the PEQ to the DBAL A3.
Lower: Running a BCM LPK in a Spikes lower and a VLTOR A5 Buffer/RE. I went with an ALG ACT in this rifle, and I regret it. I used to have a standard DPMS trigger with >5,000 rounds on it that was broken in beautiful. It was incredibly smooth. However, I didn't want a DPMS anything in my rifle anymore and grabbed an ACT. It is a great trigger compared to a new milspec trigger, but it isn't as nice as my (free) superbly worn in DPMS. I have considered a Geissele SSA-E, but I generally find 2 stage triggers mentally tough to master when shooting quickly and up close.
The rifle is zeroed to 64gr Gold Dots.