If that doesn't work, you may need to give the lockbar a little more bend. I've noticed on several framelock knives that the lockbar does not come over onto the blade tang with enough force to hold the blade against the stop pin at the top, and after a little wear sets in it allows the lock do as you have described. In fact I did this to my Military when I got it, and have done it to most of the framelocks/liner locks I have. It doesn't take much and you need to do this carefully, but it is doable. Funny, the only framelock I didn't need to do this with is one I couldn't do it with, a Lion Steel SR-1.