Easy now, a lot of the guys on here were developed in the middle of the last century as well.It means that the geometry of new magnum cartridges let me burn powder more efficiently in less time. So I don't leave almost any unburnt after 20 inches. The older belted magnums are inherently less efficient. Right now I am pushing 210gr ABLRs 2850 fps something that is not possible out of magnums developed in the middle of the last century.
I'm a few years older than you and I also am in decent shape. But this is where I'd apply the two gun rule. Same cartridge, barrel length etc just build a lighter gun for hunting. That's just me though.