I agree that high pressure is the most likely cause. Is all the ammo from the same lot? Have you ever had issues before? Excess headspace or burrs in the barrel (sometimes from cleaning) are likely culprits. Check your chamber too. I have seen a few with so much oil in them they cause high pressure. Weatherby loads are pretty "hot" pressure-wise to begin with and it doesn't take much to spike pressures above safe limits. At any rate I would not shoot it again until you get it looked at, as strong as Weatherby's are all guns have limits on how many times they can be exposed to overly high pressures. The results of an action coming from together will at best ruin the gun and at worst severely injure the shooter.