The Superformance ammo is nothing but a slow burning, double based powder that is loaded to maximum speeds in the given caliber. When ammo is loaded like this, it pushes the boundaries in keeping the ammo within normal pressures in ALL guns. Some guns will be over pressure with the Superformance ammo. I asked the question on what you were using because I have seen it many times this ammo be too hot. You need to not shoot this ammo any more, as it can cause a problem of over pressure. I would contact Hornady to work it out.