Every time you pull the charging handle back and let it go it hangs.It hangs or binds on something about 3/4 of the way forward.I disassembled it to try a find the problem.If you install the breech bolt,recoil spring ,charging handle and recoil spring guide all is well.It cycles smooth.When you install the lower componets it binds.Does anybody know of any common problems these things may have had?