45 colt is the cartridge others want to grow up to be. Potent at low velocity and will beat 44 magnum if your gun is up for the pressure, it's been run over too many times. The beauty of the big bores is that you don't need velocity unless you're trying to flatten trajectory . I was a 44 convert for a few years and gave up on it when I found a better cartridge for high & low power- not exactly 45 colt but close, 454 casull. That has not much to do with this conversation but it does relate because 454 cases can be cut down for heavy 45 colt loads which extends brass life.
I think a 45 colt would be a really sweet shooter with like a 360-400 grain bullet, and that is where it would pull away from 44 mag in subsonic loading. Unfortunately the only such bullets I've ever found are either very expensive boutique offerings or people resizing 45-70 bullets.
They're available for normal prices, just gotta know where to look
https://missouribullet.com/details.php?prodId=463&category=5&secondary=14&keywords=
https://www.midwayusa.com/product/1010707860
Those are just a couple , look for bullets intended for 454 or 460mag.
Heavier the better for me, at 1200 fps there's not much on earth that'll survive a well placed hit from that, even at 900 fps, they'll go clear through just about anything fleshy.
That said, I like 45-70 with 405 grain rnfp over a case full of trailboss. That shoots like a pop gun and still gets close to 1000 fps but all you need is another load handy for full power, more then you'll get from any handgun round. A starting trapdoor charge of imr4198 is about like a trailboss load too- works great.
But yes, I fully agree that 45 colt is really hard to beat. My normal 45 colt load is 5 grains of clays under a 250 rnfp . clean, accurate and very easy for anyone to shoot. Even that load will kill just about anything. Big bores are certainly my favorite and of them the 45s are the way to go. I think bullet selection sets them apart from the 44s and the case capacity and larger diameter are just a bonus. I've tried the 44 +p+ rounds some boutique sellers make and I've fired them, if you're specifically buying a gun to shoot those, get a bigger gun, if you just want a few for grizzly defense you better hope it's a ruger or a FA or you may not like what happens.
I'll beat the horse a little more, what the heck. Bullet diameter matters if velocity will be below 2000 fps. Hits count, misses don't and larger diameter increases the likelihood of a hit, it also makes a bigger hole so the juice leaks out faster. Those are the facts.
45 colt is the way.