I certainly don't mean to start an argument here, but I don't understand why the pre-easy open frames are weaker. I believe they just changed the pivot point of the trigger guard and made minor adjustments to some camming surfaces in order to effect opening with less force. All frame dimensions are the same, I believe, and as far as I know there were no metallurgical changes. Can you tell us why these earlier frames are not as strong? I have several of them that I've used with some pretty stiff .35 Ram loads and some .30-40 Krag, as well - no problems.
I may be wrong, but I believe the change to the easy open frame was around #190,000.
RonF