Hi, I have an M16A2 clone 20 inch barrel. It is a Del Ton lower assembly with a DPMS upper assembly and barrel. I took it to the range yesterday and noticed that I could not reach full zero, had to max out my windage all the way to the right. I looked online a bit elsewhere and some said to check for wobble with the gun resting upside down on the sights, there is no wobble. Front sight post seems like it is straight, the sight base appears to not be canted but may need a gunsmith to check it out to be sure. I've also heard of the barrels being bent. What other suggestions do yall have?

barrel is not centered in the upper,

betting if you took the barrel off, there will be some play in the slot on the upper and the pin on the barrel,

Oh okay thanks. Is this a fairly simple fix? Do you think it came like this straight from DPMS?