After I got home from the competition today, I took the rifle apart and studied things a bit.
Here are some relevant pictures.
The small block of steel in the first picture sits in the stock in the crosswise slot at the rear of the receiver channel. The top fits into the slot in the bottom of the receiver at the rear shown in the third picture.
The problem turned out to be the metal piece was slightly too tall. I know this because the rear action screw is visible through the hole it screws into when the bolt is removed from the rifle. With the metal piece removed the screw fit about one thread further into the receiver than it did with the piece in place. With the piece removed, the screw fits flush with the inside of the receiver and does not interfere with the bolt whatsoever.
Apparently, the receiver wasn't sitting solidly on the rear pillar with the metal piece in place. When I tightened the rear action screw down enough, the receiver would flex a bit and begin to bind the bolt slightly. Enough so you could feel it when working the bolt.
Not certain what purpose it really serves except to complicate the bedding. With the metal piece removed the receiver fit nicely and solidly onto the pillars with no rocking or sliding around.
I am going to work with the rifle without the metal piece for a bit and see how it shoots. I can always put it back if things refuse to work. I can also remove some metal from the height of the metal piece if I need to put it back.