Hello again,
Do you know someone who owns a 45-70 for you to shoot or can you rent one someplace close to where you live? You could try it out and so could your son at the same time. Does a member of this forum live close to you and would be willing to let you shoot his 45-70?
If your son does not do a lot of shooting... I do not think that I would just hand him a 45-70 rifle to shoot with or without factory or 'reloaded' ammunition. How does he handle recoil? I am only 5' 3" tall and smaller but I used (Before my arthritis got really bad.) to shoot some pretty big calibers in handguns, on a regular basis - NO kidding you, myself so it is up to the individual.
I shot a Marlin 'Classic' 1895 45-70 years ago and the handloads were 'loaded' specifically for me since I had an old, bad injury plus my arthritis was not as bad as it is now. My hands are much worse now unfortunately! I shot it fine - 4 rounds out of MM's former, older Marlin 1895. It was not the classic one that he has now - he has a newer one and not the former walnut/stainless steel guide gun one. I like the historical details and LOOKS of a 45-70 but if I had one - MM would shoot it or it would hang on the wall.
If I was you, which I am not, I would get a 30-30. Cheaper ammunition to buy and found just about anywhere easily plus you can reload too. Don't they shoot pigs with that just as much as they do deer, moose, elk, etc.? MM hunts animals with a 30-30, a 45-70 and a 30-06. Plus his 22LR for grouse and so forth.
You can 'load' just about anything from what I gather. I do NOT reload but my husband has reloaded for many, many, many years. Since you mentioned your reloading equipment, there is nothing wrong with simple reloading tools - you don't need some fancy or super expensive tool for that. If it works for YOU and it is simple, quality made and accurate - use what you have for your new rifle too.
Montana Man, my husband, has owned many, many Marlins over the years. When we consolidated a BUNCH of our firearm calibers after we got married, I am a remarried widow, since my hands got FAR worse, since we moved from one small place into a small home that we just finished building... he really changed a bunch of his calibers not just me. He sold his nice 35Remington Marlin 336 a few years ago and got a 30-30. Then I got a 30-30 too. I still can take that 30-30 with me for woods/wilderness/etc. protection but I ended up fairly recently giving it to him.
I am the type of person that wants to find ammunition available and at a reasonable cost even though ammo costs have gone through the roof in the last several years. Since I do not 'reload' (I can use his ammo though.) - I used to and still plan on buying specific calibers where I could not only afford the factory ammunition but could FIND it easily.
If I ever had a 45-70 - I would call it my 'buffalo gun' because that used to be in my past plans.
Best wishes to you again.
Catherine