I have an Eotech 553 mounted on my BM M-4. I wanted a flip-up rear sight that would co-witness my optic, so I got one at my local gun shop instead of waiting for weeks on an order to arrive. I originally wanted a GG&G MAD sight, which they didn't have, but I did find a Pro Mag sight that looked almost identical.
I mounted the sight, and took it out to the gravel pit where I do my shooting the next day to zero it in. I discovered that the sight is a little too low. Although I can get a sight picture with it, the bottom of the diopter is cluttered by the back of the Eotech. I wish I had waited to get a better rear sight!
Can anyone recommend a good flip-up that they know will be tall enough for use with my 553?