Recently received a used MREX MkII. While there's a MkI install video online, I can't seem to find any instructions on mounting the MkII, since KDG indicates there are some differences in procedures. Disassembling the barrel/upper receiver group was no issue for me though.

Is the upper bridge that runs between the OEM picatinny side rails supposed to be removed completely or secured in some fashion? It seems the square nuts aren't needed anymore, as is the case on the Mk1.

Also, how many KDG screws is the MkII supposed to come with? For some reason I only got 2 (one short, one long), and I know the FN OEM lower handguard screw is too long for the KDG lower handguard bridge. My hardware didn't come with any buffers, and the torx screws that go into the side pic rails are countersunk - don't see how they'd secure the rail to the receiver.

Don't know about the MK2, but the MK1 was fairly simple, once I got the factory Scar Torx bolts out. They were a bear. You'll definitely want to use a small torch to heat them up. I had one of those small butane torches. The first one was the most difficult as I was tentative as to applying too much heat, but once you get the feel of the first one, in terms of duration, the rest come out pretty easy. I actually buggered up the first one, but extra bolts had come with the MREX. Good luck, you'll be glad you installed one.

Yeah, that worked. I actually used a kitchen torch to take care of the threadlocker. Fortunately nothing stripped in the process.

Apparently the guy that sent me this thing took the bridge out of the handguard, even though that's not supposed to be done, and doesn't look like he included the three screws that secured it... this will be fun.

I just finished installing a Mk II and also have a Mk I. The Mk II was simple to install. The rail comes with the lower bridge installed and don’t need to mess with it. The upper bridge and square nuts in the receiver aren’t needed anymore. Once you affix the rail to the barrel extension with the T25 screw (62 in/lb), there are just two screws on the side to help secure the rail to the upper. I think these smaller screws are T20 (50 in/lb). Contact KDG... they’re good about sending screws.

Yeah, I asked them if their hardware kits were expected to be in stock. Haven't gotten an affirmative on that.

I was second guessing myself at first when I got my MkII, since my Midwest Industries extension required that extra step and the MkII didn't. Once I RTFM, I figured it out. Very happy with it though, even though it's adding a 7th shade of FDE to my SCAR.