View Full Version : Mounting an Eotech 512 sight on a Stag 2H upper

06-03-2008, 1:40 PM
I don't appear to have enough room on the picatinny rail of my Stag 2H upper to keep the rear flip up MI sight mounted and have my Eotech 512 mounted at the same time.

Has anyone else encountered this problem and if so, what did you do to resolve it?


Paratus et Vigilans
06-03-2008, 1:59 PM
I'm not familiar with the way the MI works or deploys, but it sounds like you either need to get rear BUIS that take up less room, like the A.R.M.S. #40 or #40L, or you need to put a railed forend on it to move the EOTech partially onto the rail.

06-03-2008, 2:06 PM
Not sure what you mean here bud. Can you post a pic? The MI ERS BUIS should be the same size as the ARMS #40, so you wouldn't be gaining any room by switching. Because it houses 2 AA batteries, the EOTech 512 is a long sight so it may extend over your handguards a bit.

06-03-2008, 2:11 PM
If you've got fat M4 handguards, it won't go far enough forward because they stick up over the rail plane, right? You could go to slimmer handguards, or railed handguards, so the front end can hang off the end of the receiver. Another alternative is to file down the handguards for clearance, since they're the cheapest part.

How many slots and rails does the MI BUIS cover, and is it the MI ERS or the MI MCTAR-SPLP? The ARMS 40 covers one full rail in front of the slot it's mounted in.

The newer model Eotechs fix this by having some extra relief cut in at the bottom of the battery compartment.

06-03-2008, 2:18 PM
After I mounted my 512 on a 2HT upper, I noticed that if I had in fact gone with a 2H it would have hung past. You might be limited to removing your flip up sight, or getting a smaller eotech. I'll post a picture when I get home of what mine looks like mounted on a 2HT (hopefully I remember to) :D

Edit: I just thought... you could get a riser and might be able to clear it that way, and still maintain a co-witness...

06-03-2008, 2:19 PM
didn't have a problem with installing my eotech
10/30 mag

06-03-2008, 3:59 PM
I didn't have a problem either with mounting the 512 on a 2H upper. I do like the way they co-witness.

06-03-2008, 6:22 PM
Mine went on fine just move the BUIS all the way back and put the 512 on there.