Question 1. Yes
Question 2. I'm not sure but it could be as simple as a mag box and follower change.
Option 1. Rebore to a 358 Norma or 358 STA
Option 2. Have Redneck " smith on here" look at the barrel. The barrel might be good and the throat shot. Set the barrel back and use my reamer to rechamber to 7mm Mashburn Super.
Option 3. Again check the throat and barrel. If the barrel is good. Set the barrel back and keep your dad's caliber. Nothing wrong with having 2 7 mags. This is probably the cheapest option.
I'm not a smith but I like guns a lot. And I slept at a Holiday Inn Express last night.
