Back to the 25, I originally built mine specifically to run heavier bullets like the 130gr Wildcat when you could still get them. They were, at the time the only game in town building heavy for caliber bullets for smaller calibers. It was also due to me having an almost endless supply of '06 brass that I wasn't really using for anything else. I settled on the 120gr bullet due to availability and the fact I was getting exceptional velocities and accuracy out past 300yds. Just recently I have picked up several of the newer 130 grain range bullets to try but just haven't had the urge to get out in the heat and do anything with them.
During my initial work up phase I did try some 142gr Wildcat's but just couldn't quite get the velocity up enough to stabilize them. I'm hopeful that the latest 130'ish bullets will shoot as well as the 120's have. I only use this rifle for hunting deer or feral hogs so I really only run a half dozen or so rounds through it a year, mainly to check zero and if we're lucky stock the freezer.
With a longer barrel and using the newer slower powders some of the AI conversions are really an alternative to the magnum versions for certain calibers. There will always be this or that new calibers that folks get to clamoring about, but for some with a limited budget, as intended P.O.'s simple re-chamber can provide an opportunity to stretch their legs.