"Custom" M-LOK Picatinny Rail Mount/Riser

[Big Frank]

First of all, I know this is a hack job, and that's okay. I'm not proud of the paint job either, but I'm usually not. I cobbled together something I need, and I won't know if it works or not until I finish my AR upper build. I think I figured out where and how to mount my red dot - on the upper right of the handguard. If this works I'll be able to mount the red dot in the same plane as my backup sights and not have it blocking my view of them, unlike with the with the 45 degree offset mount I bought. I was looking online for red dot mounts using an Aimpoint Micro footprint. Either one that mounts to the scope tube, or an offset Picatinny mount. I want to be able to see the red dot between the scope turrets when I cant the rifle. The mounts I was able to find were mostly in the $150-$200 range.   I think I came up with a cheaper solution, and I don't have to wait around for an expensive mount that's not in stock. I had a 5-slot M-LOK Pic rail and an 8-slot M-LOK Pic rail that it looks like I wouldn't be using for anything. So I made a piggyback riser out of them.

I drilled a hole through the center slot of the small rail, and through the center bar of the big rail. I threaded the hole in the small rail 1/4" NC, and re-threaded a bolt to fit it. I drilled the hole a little bigger in the other rail. After I made sure it was going to work, I drilled the screw holes in the small rail big enough for the screws to drop through to the big rail. I glued it all together with JB Qwik and let it set up. Then I cut off both ends of the bolt and filed the top of it down to clear the center slot. I filed the the bottom of the bolt flush with the rail, and filed in between the M-LOK lugs. I drilled out the screw holes that were full of epoxy, and drilled the top holes 1/64" larger. Then I used a large rat-tail file to file the excess epoxy off between the rails. It was still a little gummy and I couldn't get a smooth finish. It's full of aluminum flakes too and looked bad. After I was done with all the filing, I spray painted it a few times. I didn't see the little booger on the rail, circled in the first pic, until after I took the pictures. So I flicked it off, since that seemed like the appropriate way to get rid of a booger.   I've been working on several things on different guns and doing this too, so it's taking longer than I thought it would to finish my AR upper. If this works, I can mount the SIG Romeo-MSR without using any additional mounts or risers, just a low Pic rail mount screwed to the red dot. When I flip up the backup sights, I should be able to look right through the red dot to use them. That way I'll have a 3-9X scope for longer ranges, a red dot for shorter ranges, and irons as a backup.

I don't remember how much I paid for the 5-slot rail, but the 8-slot rail came with the handguard. So, this custom rail-mount/riser isn't free but it's only a fraction of the cost of the mounts I was shopping for. And it's rock solid.

[Big Frank]

I forgot to mention yesterday, the main reason I cobbled together this double rail is because I couldn't use a single rail, with or without a low mount riser, like a 1/3 co-witness plate. The edge was so close to the edge of the top rail I couldn't attach the red dot. Now that I've doubled the height, I can use the top rail and forget about the bottom half. But I think I'm going to file the sides flat like in the last illustration of the double-rail, as it looks now, and how it should look afterward. The space is so small, I'm not sure if there's enough room to put rail covers on the top rail, but there will be if I grind off the unnecessary projections on the sides of this riser mount.

[Big Frank]

So, I ground, filed, and sanded the sides of this thing flat and had it looking good. I filed and sanded the old crappy paint job off as I was working on it, and thought this is going to look a lot better next time. Then I cut the useless extra slot off each end of the bottom rail, making it a 5-slot on top of a 6-slot rail. More compact and much better looking. But, before I could finish filing and sanding down the ends, the whole thing started coming apart. The epoxy wasn't sticking to the anodized aluminum. I finished sanding the ends down, then tried pulling the 2 halves far enough apart to make small gaps down both sides. I spread Gorilla super glue on both sides and tried to get it in all of the small holes, then I squeezed it together really hard in the vise. I don't know if any of the super glue made it down inside, or if it will stick to the aluminum and epoxy even if if it did. It would suck to find out I wasted more than 2 days and destroyed 2 parts for nothing, and still need to buy an expensive red dot mount.

Now we know why people say FML. Murphy was an optimist. Things are even worse than he though possible.

[Diamondback]

I'd say use the epoxy as a temp while you have a metalworker braze or weld the two pieces together. I'm looking for someone to do that with the optic risers that make up ASDW-PIP's coupler so I can get rid of that rail-to-rail clamp and not have to remove the coupler to use the sights.

[Big Frank]

Well, it seems to have stuck together okay, so I sanded it a whole bunch and painted it several times. I should have used a file to cut through the anodizing and scratch up the surfaces real bad so the epoxy would stick better. The same way to need to break the gloss on some things to get paint to stick. It's not perfect, but hopefully it's good enough.

[Sponsor]

[Big Frank]

So far so good. It looks like the insane glue is holding.