Well, if the rear of the magazine should be in "recoil contact" with the stock then I've got some work to do!  I've got about 1/16" clearance behind both the left and right sides.  It's a wonder this stock never split since the recoil was being transfered only by the tang at the wrist.

A bit of backstory may be in order.  I took this sporter to the range today for the first time.  At 50 yds my 5 shot group was about 6" in diameter.  This is shooting off a sandbag.  The rifling is sharp, crown is good, throat not washed out, sights not loose, so I figured it must be the bedding.
I took the action out of the stock and dripped a small bead of candle wax down the centerline from the end of the fore stock back to the trigger slot.  Installed and removed the action and what do you know, the wax wasn't mashed down anywhere except right at the front trigger guard screw.  Turns out the barrel wasn't resting in the bottom of the channel but was contacting high on the sides.  No wonder things were shifting around from shot to shot.
I measured the barrel contour along its length and wrapped sandpaper around various sized socket wrench sockets in order to open up the channel.  Now the barrel rests solidly in the channel along its length.
Now to shim the wood behind the magazine.  Popsicle sticks come to mind for material.  We'll see.