This looks like a good project gun. I would try changing out the ejector rod housing first. A "dead man" can be placed inside the tube next to the screw placed on the inside closest to the frame and may be necessary to take the recoil impulse stress off the screw that holds the ejector rod tube in place. The screw can loosen with repeated shots and it is a common problem with heavy recoiling calibers.
Jack Huntington of JRH Advanced Gunsmithing has developed a technique to do so and can describe how you can approach it. I hope this unspoken concern can be a worthwhile starting point.