Try loosening the side that the barrel is pulled to, and re-torque the opposite side. Then torque down all the screws in the proper order.
You can also loosen all the screws, physically pull the barrel to center, then step torque the barrel to keep it centered.
(Step torquing is done by first torquing at 25inch pounds all the screws in proper order. Then torque all screws in order again at 45inch pounds. Then final torque at 62inch pounds)
On the sight in; did you use the front or rear sight for windage?
From experience changing barrels on the scar, I have had to re-torque em before to get him close to centered.
From there I have usually been 2-5 clicks in windage at the front sight to zero the iron sights on the rifle.
If these things do not work, give FNH a call and send the rifle in for them to inspect or repair it.