Photo's would help,
Hence remove the rear sight and take a photo straight down the top of the upper receiver rail for referance so we see if the FSB is canted off to the left of upper receiver rail center line.


Next, shotgun the open, and take a photo of the center of the feed ramps against the front take down pivot lock straight down the center line of the lower receiver.



Best case, it just the barrel that slipped in the upper receiver when the barrel nut was being tightened, and this should show up with the FSB canted to the left of center line of receiver, and the center feed lips rotated off center of pivot block the same way.   The quick fix on this, pull the upper off the lower, put the upper across your lap, with with weak hand, hold the receiver alone on top of that leg, protrude the FSP just past the other leg, and using a non marring leather mallet, you can strike the FSB just above the barrel to slip the entire barrel and barrel extension in the upper receiver barrel socket to correct the barrel index.



Worse case, either the front face of the upper receiver barrel socket is not true to the center line of the receiver, the barrel is bent,  the upper receiver barrel socket was bent by too much torque installing the barrel, or even there is debris between the back of the barrel extension and mating face of upper barrel socket lip that is causing the bore of the barrel to not be on center line of the upper receiver.  Here the barrel needs to be pulled from the upper receiver, and the problems corrected before the barrel is reinstalled correctly.




P.S, Mil spec is 13 click off center is acceptable, while I go for rear sight being dead center zeroed via slipping the barrel in the upper receiver via fine tuning with the leather mallet with live fire to confirm the index slip at the range instead.

Front sight wrong, as in the FSB not indexed against the barrel extension pin when the barrel was produced, or the barrel just rotated in the upper barrel socket when the barrel nut was being tightened to cant the FSB off line of the upper receiver instead?

FSB looks to be canted to the left, and as for the barrel feed lips to the receiver, can't see that well enough to see if the problem is a rotated barrel during assembly, or a problem in the barrel to upper receiver socket at assembly.

If you bough the upper built, then may want to warranty it out to have it corrected (barrel pulled and the upper receiver socket/ barrel install corrected).

Also for grins, to weed out a problem with the rear sight being defected, mount it backwards on the rifle and zero, since it could be that the rear sight is leaning hard to the right when installed, and making you crank it to the left to solve it own leaning problems.