I picked up a Marine corps tech manual on an M-16 to help in the assembly of my first AR.
First off I ordered a complete bolt assembly from AMEETEC. It has what looks like a heavy oil inside of it. Do I need to dissassemble and relube it?
Does the charging handle get lubed in its race way?
Buffer spring? Lube it?
Bolt area in upper assembly?
What is the best lube to use?? I have the Molybdenum stuff for the buffer tube threads.
I would clean and lube the bolt/carrier assembly, new parts sometimes have junk left from the manufacturing process that you don't want in your rifle. It can't hurt.
The best lube? Their are about 1 million answers to that. Any good quality gun oil or CLP will work fine.
Everyone has their favorite, try some different stuff and see what works best for you.
There is some good info on lube (where and how much) here.
It's a zip file from Bushmaster, pages 4-16 should answer all your questions.