I understand being a bit bent out of shape, but
You told him it was "okay" hed didn't change out the FH for you. So IMO, you're SOL on that. You agreed it was okay, but now it's not? Guess you're not the 'smith you thought you were.
The rifle was built out of spec by Colt. Call them and deal with them.
The fact you were too busy is not his fault.
As far as the rifle not running properly, is that fixed now? That may be the only area you have a legit complaint witht the dealer, esp if he told you it ran flawlessly before the sale.
I do feel your pain. I bought a pre ban during the ban from well known vendor on the boards and was told it was "immaculate" with a low round count. I have never scraped more carbon from a rifle than that one! Dirty is an understatement. Live and learn.