I have a friend who lost the bolt to his chrome moly long action Rem 700 in 7mm Rem Mag. We found a used bolt on the internet that comes from a stainless model 700 in 7mm RUM. I believe the bolt face won't be a problem, since the RUM has a rim diameter of .539 and the Rem Mag has one of .532. Should be close enough, right? I am concerned about headspacing and timing. Are Remington's tolerances good enough to allow switching of bolts without headspacing/timing issues? I know that this may not be a perfect situation, but is it good enough from a function and safety standpoint? Thanks!