Guy on the bench next to me had the wrist snap on a Weatherby Mark 5 (wood stock) a couple years back. Not sure if sled contributed or if the wrist was just ready to let go. Grain through wrist was reasonably straight and showed no signs of previous fracturing or obvious flaws in grain structure.
That gentleman had to much weight on the sled. That is a common problem with the lead sled in that people figure that 5lbs is good 20 is better. They put so much weight on them that they can move anymore. Recoil has to go somewhere so it finds the weakest spot. On a heavy recoil gun it is the wrist of a stock that loses the battle. I have seen several guns that have broken at that spot.
