i have taken my barrel from an A2 reciever, and attached it to a flat top reciever. i have an eotech on a 1/2 inch riser mounted on the flat top. i want to add a flip up rear sight, if i mount the sight on the flat top reciever it won't be tall enough to look through the eotech. question: if i mount the sight on the 1/2 inch riser behind the eotech will it line up with the front??????? i'm not trying to co-witness, just want a rear sight, if the eotech should go out.

IMO, I would look at the different ARMS 40 series of BUIS. Thats just my opinion, in this forum, you will have many, many others who may suggest another one. I have 2 Bushmaster AR's. One is a carry handle ( A2 ), the other is a flat top. Both are the 16 in barrel M4 type. I also have EOTech's on both. On the carry handle one I have the model 551 on a Bennie Coolie mount that puts the 551 between the front post / sight and the carry handle. On my flat top I have the 552 w/ no riser, a ARMS 40 low profile stand alone rear back up / flip up sight. The only modification I did to this one was put a bigger front sight post ( .040 ) that Bushmaster suggests.
Obviously, I do not if it would work or not for you, but in theory it sounds like it might. What I think you might have a problem seeing, through all of your details, is the front sight post going to be able to use your rear sight. I guess there is one way to find out, get your project together and see if it will work.
Good luck with your build, and I hope to hear back from ya in regards to your project here.

dont think the taller front sight post is going to help you with what you are trying to do.


if im not mistaken the buis should be seeable through the eotech window.