Does anyone have a mounting solution for the Holosun 507K? Considering its a smaller sight, none of the provided mounting plates work! I am quite disappointed at this point to say the least!

Thank you in advance!

I have the same issue.

It mostly fits the #4 plate, and should be fine with some modifications. First, the rear lugs will need to be milled smooth. Then, the front lugs will need to be sanded down about 1mm, to eliminate the gap between the optic and the base plate.

I’m waiting until I get a spare #4 plate in before I fuck with mine, but don’t really expect any issues.

@SimonPhoto have you had any success yet?

The Holosun is sitting in my closet still, unfortunately.

That said, my wife and kids are gone for the week and I have some time. I’ll make it a point to go ahead and make that modification this week and let you know.

It looks really straightforward, though. Easily done with just a hand file, really. I prefer to do things the “right” way, even when it’s more complicated and expensive, and was planning on having the plate powder coated when I’m done. Given that it’s been a month and I’ve not touched it… screw it. I have a Sharpie.

I had some time during a meeting, and was able to mount the optic without issue. Some notes:

The front lugs on the 04 baseplate were 1.0mm tall. The Holosun HS507K indents were 0.7mm deep. I filed the front lug down to approximately 0.6mm, using the sight as a reference, sitting it on the baseplate backward (the rear lugs were still present at this point) until there was no light visible under the lugs. At that point I measured the lugs, and they showed 0.7mm. I filed them down a few more light strokes, and they now measure at ~0.65mm.

I filed the rear lugs level with the surface of the plate. I wasn’t super careful not to mark the plate itself, so I filed until I was making contact with the plate on both side of the lugs. Once they were smooth to the touch, I cleaned up the places where I removed material with an old trigger stone, just to make sure I didn’t have any burrs sticking up still that would interfere with the mating surface. This step is probably unnecessary.

Finally, I used a black Sharpie to paint over the exposed metal. It doesn’t match and looks like shit upon inspection, but it’s “good enough” for the moment. If that bothers me over time, I’ll refinish it. I thought I had some Birchwood Casey “Aluminum Black”, but can’t find it at the moment. I’ll go ahead and order some more, and if the mismatch bothers me I’ll tear it back down, strip the paint, and hit it with that. Matte black spray paint would almost certainly work just fine as well as long as it was applied lightly and evenly.

I’ll attach in-progress images from my phone in just a moment.

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Thanks for posting this! Can you use the rear sight on the 507k with your front sight or is the optic too high?

Interestingly enough, the new SFX METE comes with an optic cut specifically for the smaller footprint RDSs. I don’t know if the 507k is included in the plates in the box, but since they are plastic they will be a lot easier to modify if necessary. I modified my Elite SC for the 507k and it took maybe 5 minutes and works perfectly.

Thanks for this thread OP. Bought my first RMRs today. One went on my Sig P365 XL this afternoon. That was a 5 minute drop-in. Will go to work on the #4 plate on my Canik tomorrow to get it ready for the other 507K.