First of all, welcome to the Forum!!...When I was reassembling the rifle I noticed that the trigger guard seems to be binding up and it is difficult to return to it's proper location. It does this in it's factory synthetic stock & a cmp GI walnut one. When I insert the trigger group into the stocks without the barreled action, it does not bind, in either stock. When I invert the action & insert the trigger group sans stock the trigger guard does not bind. It is only when assembling all 3 of the main groups together. There are two small "arms" (forgive my ignorance of the correct nomenclature) on each side of the trigger group that move when the trigger guard is rotated. They appear to be binding & I can see wear on them already...
What you're describing is normal. The M14 operates best with some tension between the front end of the stock (the metal part, AKA ferrule) and the front band lip that hooks under it. The two small arms on the trigger group hook onto the receiver legs and pull the receiver down onto the stock as the trigger guard closes; like a see-saw, the barrel gets pulled up and creates that tension. Of concern would be no resistance when the trigger guard is locked up.