I disassembled my Springfield loaded model's NM rear sight in order to install a hooded NM apeture sight last night. I finally got everything back together and I now have about 1/16" to 1/8" gap between the back of my receiver and the rear portion of the rear sight base. Everything works but I have this big gap. I forgot to see if this gap existed before I took the sight apart. I looked at my SA standard model and the GI sights are sitting right on the back of the receiver. I disassemblled it too and put it back together without problems. The NM sight on my loaded is the ball bearing type. Am I missing something? The rear sight cover doesn't look nearly as well snapped in as the standard, but it is in there correctly. please help. thanks Billy