Has anyone used a new Geissele MK4 MLOK handguard with a Seekins SP223 billet upper? I believe the combo should work but wanted to double check. I don't want to have to alter the MK4 to use it....

SP223 upper

You can ask in the Geissele Industry section, they might know. I tried an MK8 on a Mega Billet upper receiver and it did not cooperate. I ended up going with a standard forged instead. As you probably already know, they state their rails are only designed for milspec forged receivers.

 

I asked in their section days ago and haven't received any response.....

As long as the two tabs with the set screws fit around the upper there shouldn't be any problem correct? The Seekins upper has fit every handguard I've tried so far because the front of it is thinned down to allow the anti rotation tabs to fit properly. I want to say the front of the Seekins was designed to have milspec dimensions in the front of the receiver but I could be wrong....

I took the rail and put it on over top of a SLR barrel nut and it appears to fit fine....would switching barrel nuts change anything?The SLR nut is a smaller diameter than the Geissele so there is a bit of play but when you press the rail upwards it goes about a millimeter higher than the upper receiver and when you press the rail down, it goes an equal amount below the upper which sure makes it seem like it would be perfectly level on the larger Geissele barrel nut.

I unfortunately don't have a vice at my current living situation to do the assembly myself so I'll have to take it to someone. I don't want to have it fully disassembled just to find out it won't work....Any thoughts on the above info or pics? I sure want this set-up to work. My goal to finish up this rifle is to make it as "bomb proof" as possible which is one of the reasons I went with the Geissele rail over the SLR....I also added the tougher Kahles scope replacing a Viper PST 1-4X, replaced the RCA bolt that came with the Noveske BCG with a LMT Enhaced bolt, swapped the BADASS safety levers with the dovetailed BASCASS model and last I am swapping the SS Noveske barrel with a Noveske chrome lined model....it should be one tough badass rig when it's finally assembled....

pic removed

It turns out the Mk4 rail works perfectly with the Seekins SP223 billet upper....and looks killer as well

Geissele makes a very nice handguard!

A little unrelated, but I have a MK2 that Jason Curns, from Mega, took some material off to fit on my Mega GTR-3H upper.....pretty gnarly stuff. Good luck!