Originally Posted by
bootsmcguire
I believe what Stangfish was trying to convey was that a twisted action will cause the scope base holes to be mis-aligned, and an easy way to see if your action is twisted is to insert two long 1/4-28 bolts into the action screw holes and see if they are true to each other. If they are not then the action is twisted and your scope holes won't line up.
Flat backs can be a problem child if the person hand grinding the rear was having an off day, but also because people will sometimes see that flat as a place to try and affix a crecent or "monkey" style wrench to in an attempt to have a cheap action wrench and in doing so they twist the actions and cause themselves all kinds of grief and eventually sell the rifle to another unsuspecting buyer.