So cool I had to name it. But before we begin, a disclaimer: This is not made by LaRue Tactical so don’t flood Mark with a billion phone calls. LT had nothing to do with it except to provide the best rail out there as the starting point. If you don’t like it, think it looks like crap or is quite possibly the dumbest thing you have ever seen since The View, that’s on me and me alone. Alrighty then, let’s get on with it.
A little background. Overjoyed with the recent release of some CT legal Colt carbines, I bought one and started to make some modifications that I had though about for a long time. I noticed that a lot of you had began to run your lights at 12 O’clock which makes a lot of sense in a lot of situations. I like SF X300s or SF M600 Scout Lights right now but I knew that the X300 was the better way to go because of its compactness. I was also planning on using a SF XT07 tape switch but was willing to ditch that if I had to.
Looking at the offerings from rail companies out there for one that would have a rail forward of the front sight post at 12 o’clock, you are somewhat limited. Of the ones I saw, I always liked KAC for other parts so I went with the KAC MRE. Very nice rail but it had a couple of problems for me for what I wanted to do. First, the rail had a large cut out on the bottom where your bayonet lug would hang down. The cut out is exactly where I would put my FUG vert grip. Secondly, and more importantly, the rail space ahead of the FSB was short. An X300 would lock on without the XT07 attached. The really long XT07 attachment point on the rear of the X300 hit the FSB, preventing the light from locking in.
OK, so I could ditch the switch and just use the rocker switch that comes on the X300. Unfortunately, the inability to place the FUG where I normally would wouldn’t allow me to manipulate the light with a chicken choke hold on the vert grip as I do on other rifles. Plus, the exposed barrel section gets really hot after awhile.
That’s when I thought of this. In my mind, it had a lot of pluses. One, it was a LT rail, my favorite. Secondly, it was one piece for strength for my rail mount M203. And last, and admittedly a driving force, is that I have never seen anyone else do it. Of course, when it came to finally getting it done, I could see why.
When I first posted the MT6400 with the KAC, I think it was another member that mentioned something about replacing the standard FSB with a railed gas block and folding front sight. That was exactly the idea I had for the LT except I used a KAC GB to accomplish the same thing. So I took all of the parts down to JOJO’s Gunworks, my friends and gunsmiths and told them of my plan. After much discussion, name calling, bribery and hope you know where to get another LT 13.2, they let loose.
For the sake of ease, strength and CT legality, I made the decision to mill the bayonet lug off of the KAC GB. A freaking $500 part but it would make everything better. Ease and strength came from not having to cut another section out of the bottom of the rail for the bayonet lug to stick out. This maintained the structural integrity of the rail. Since this is a post ban rifle, if I wanted to maintain the lug, not only would I have had to cut out another section but I would have to use the upper on a pre ban lower. I waited nearly four years to get a factory Colt rifle and I was not going to play mix and match again.
As this KAC GB was a set screw model and not a cross pin, another small hole was drilled in the bottom of the rail for the set screw to be accessed. The GB was rocksetted and set screwed on. It was test fired on a M-16 lower with some full auto fire and worked perfectly. I took the XS Sights tritium front post and installed it in the KAC because I really like it in conjunction with the CSAT on the LT BUIS.
The cuts came out great as I hope the pics show. I think this whole project took the better part of a day to do once they got going. Can’t say they would be eager to do another one. 
I traded some gear for another Aimpoint T-1 in an LT mount when I picked up the upper. It seemed to go perfectly with the setup. I like it. 
Just kidding, it looks great.