Some factory Hornady loads have been reported to be too hot for a Handi, I wouldn't be surprised if the Superformance is, try some regular 22-250 ammo and see how it performs, sticky barrel release and hard to break open are signs of too hot a load. You can tell if it's too hot if you look for a gap between the standing breech and barrel face, if you can see light when looking across where they meet after the shot before you open the action, the load is too hot, or the barrel isn't fitted properly. Remove the forend and see if the barrel is tight to the action when it's lock up, it shouldn't be loose at all.
Tim