I grabbed the first four hunting rigs in the safe and took the trigger guards off:
Just completed McMillan Mountain Rifle:
Bell and Carlson LVSF, 243W:
McMillan Sako Varminter:
Savage 112J single shot heavy barrel, 25-06:
When the bottom metal has to flex to fit the inletting when tightened, the action screws pull the receiver at an angle. Combine this with a tight fit in the inletting and it can induce quite a bit more stress than you'd think it could. You can easily check this with an inexpensive magnetic base dial indicator. On stocks where the contact appears to be excellent, putting some DyKem layout fluid on the inletting and snugging the bottom metal down will show how much (or how little) contact there really is....even when it feels solid.
Much like properly fitting bases to a receiver and scopes to the rings, maximizing contact area pays off in reliability and consistency.
The only time I don't bed the bottom metal is when I use the 'Holland' style pillars from Holland Gunsmithing. These have an internal 82 degree shouldered screw with an Allen headed recess that is also tapped for a short screw to hold the bottom metal on. The lower edge of the pillar is fitted slightly above the inletting so that when the bottom metal is tightened down, the bottom metal is supported by the raised circumference of the pillar and has no contact with the inletting at all. By doing this, the bottom metal/trigger guard is no longer an 'active' part of the bedding. Here's a McMillan Remington Hunter pattern stock I did recently using this style pillar. The factory bottom metal inletting and pillars were a mess with the front of the inletting being .025 higher than the rear and the pillars being loose. Since that all had to be addressed on the mill, it made sense to use the 'Holland' style pillar setup:
It turned out pretty well:
Good shootin'
-Al