I am building my first AR. Thanks to those who helped me with my questions on barrel lube. I ended up getting the "permatex" ani-seize lube and using it.
Next problem I have is this. I installed my barrel as per spec. I tightened and loosend 3 times using a torque wrench set at 35lbs. I then proceded to tighten to the next slot on the barrel nut to ensure gas tube clearance, because there was a "tooth" in the way. FWIW, I had to torque to about 80lbs to get it there. I hope this is ok.
Well my question is this. It is a Post Ban Carbine barrel. The hole in my upper receiver matches up perfectly with the slot in the barrel nut, leaf spring, and locking ring. I can insert my gas tube from the receiver end only up to the point where the gas tube has a bend in it. I cannot insert the gas tube from the barrel side (without having to bend the gas tube alot in order to clear the front handguard retainer. So do I gently force the gas tube through the receiver in order to get past that bend?
Try loosening the barrel nut just a hair so you can diagonally slide the gas tube in from the barrel end (gas tube will look like it's coming out of the upper at an angle when fully inserted).
Then, retighten the barrel nut until the gas tube points directly at the opening in the front sight base.
Insert into front sight base. Align roll pin holes, but don't pin it yet!
Double check for straightness by inserting bolt carrier with bolt removed.
If there's no alignment or binding problems with the bolt carrier you're good to go.