[pabryan]

#83 rear buffer stop nut push it in and turn it 1/4 turn that will lock it in the buffer tube and keep it from popping out. Just a guess at what you might be asking.
Sorry if misunderstood handgaurds can be much harder to get in place then Ar15 handgaurds. There is a slot at the end of the handgaurds at the spring end do not attempt to fit spring inside the slots. The very end of the handgaurds is what compresses the spring. Stand gun on buttstock and compress spring with both hand gaurds at same time. (helps if you have friends help) then with spring compressed sneak opposite end into front site end.