The screw holes up front are shallower, most all manufacturer's use the two different sized screws with the X-Bolt. Make sure you have the correct length bolts in the correct location.
10in lbs up front & 20in lbs out back is what Murphy Precision recommends, so that is what I used with blue Loctite
I am curious about one thing, did you put a bubble level on the rail after you installed it? Was the front and back in the same plane or was there a slight difference between the two?
It took 2 tries to get the rail on the newest X-Bolt flat and square front to back. I thought I was going to have to bed it. I apparently was inducing a twist into the rail with the method I employed tightening it down. Baby steps fixed it.
