My 550 is the same Gary, annoyingly hard to open, you seem to have to find just the right spot or angle to push on the stud to get the blade out. It feels (to me) the stud is located too close to the pivot. When you find the spot it is nice. For this reason the 550 has had much less use then I would have thought, I even had a custom scale made for it in Black and Tan G10. It is also a Gen1 that cost over $400 here when the customs regulations made them MUCH harder to get.