I have been staying out of this up to this point. I have read the many responses and thought patterns of each of you. I have done some thinking on it too. I also have a mechanical engineering back ground. 1st of all there is a difference between stretch and flex. If you have a metal that stretches you have over stressed it, period. From this point on I am going to be talking about flex, where a metal yields, but returns to it's original shape/form. Yield point is the point where a metal has flexed all it can and still return to it's original form. Beyond that it has yielded and been damaged. Even a finger being pushed against metal will deform it, it may be very, very minute, but it yields. I think it has been established that all metal "flexes". I think the disagreement here is how much the frame flexes under stress (being fired). With out the aid of very precise measuring equipment we are all speculating, at least using empirical judgment. From this point on I am going to do the same thing. I am going to use empirical judgment. If a frame were to flex .003" in the distance between the hinge pin and the breech face, I would think it would be reaching it's yield point. I seriously doubt if the frame will stretch that much with out damage being done. The frame has been heat treated, this makes it "hard". That means it will flex even less before it reaches it's yield point. I do not think that any frames are reaching their yield points unless there is a considerable overload fired. When we look at the forces between the barrel and the breech face. Newton's law says that for every action there is an equal and opposite reaction. When the barrel and the frame are in a resting position (unfired) there are forces being applied. The latch is holding the barrel lug down and the is some force being exerted on the hinge pin. When a round is fired, the case grabs the case wall and the case stretches to the rear. That is where the force comes in. So now you have the case pushing against the breech face. The center of the case (primer) is roughly .75" above the center line of the hinge pin. The barrel wants to push open. The latch is preventing it from opening. I think that most of the stress and "flex" is in the lug. When we think of frame flex in a Handi, we are generally talking about the action popping open to different degrees. The higher the pressure, the more flex (opening the action). This is the latch yielding and the lug area around the hinge pin crushing down. In a properly locked up action, the lug and latch can compress enough to pop the action or at least leave it gapped more than before firing. I believe this happens every time it is fired. In a normal load the yield in the latch/pin area springs back to it's original place or close to it. I am talking very little here. Over time however the case stretches enough that it needs to be full length resized to shorten it enough to work in the gun again. If the load is high enough, the case stretches (used properly here) enough to push the open the crack in the breech/barrel and it can not come back into place. If severe enough it will lock up the gun. What is the frame doing through all of this, not much. Yes it has to flex, if it did not, it would break, but it flexes very, very little, definitely not .003". I think that when people are talking about how flexible the Handi action is, they are really talking about the action trying to open, not lengthen as in frame "stretch". I could go on and on about straight line forces, levers on and on. I hope you followed my way of thinking and it makes sense to you. Just my 2 cents
