FF rails don't line up with upper receiver
I installed a UTG FF and after tightening down the nut, the rails are now very slightly misaligned with the upper receiver rails. I mean very slightly, only about 2 degrees (estimate). I am usually a real stickler for details like this, but the only solution I can think of is to buy a dedicated tool that lines these up and it is not worth the time or expense if this is nothing more than an aesthetic issue that can't be noticed unless you view the rifle from the buttstock or barrel end and look for it. Any potential problems that I am missing here?