.44 AMP could've been a contender with Callahan's endorsement by itself; if only more stuff had been chambered for it, even if was limited to carbines/rifles
I think the problem is that the Auto Mag pistol was never not a shitshow in its day, and it didn't help that ammunition available wasn't much better. Cutting down .308 Winchester cases to make .44 AMP ones was typical, but this was done pretty sloppily a lot of the time, you could go look at a box of some of the factory ammo from its day and the length of cases could actually vary some within one box. Compare to early American market production 9mm Luger ammo, which could exhibit the same problem at times, it's no good.
.45 Winchester Magnum does basically the same thing but has remained easier to find (comparatively), and is available in more pistols, such as the Grizzly and Wildey, which were far better put together.
.454 Casull could've been more of a thing too; but I never saw it used by anyone other than Taurus, Ruger & a few bespoke wheel-gunsmiths.
I see it here and there, it's no widespread staple but it's far from dead. .454 Casull not as popular as .44 Magnum because it's a lot more gun to handle, .44 has kick but not so much that it's tough to get used to, while .454 has the kind where depending on your grip, you can feel the recoil slap the palm of your hand with each shot. There's a reason the Ruger Blackhawk, Freedom Arms Model 83, BFR, and other single-action revolvers in .454 Casull always have a Bisley style grip, because most people would not enjoy the feel of it when recoiling with the traditional Colt plow grip (especially when it rolls in your hand). Similarly, the Ruger Redhawk and Taurus Raging Bull have rubber grips with finger steps to give you a solid grip and to cushion the palm of your hand.
Even this way, these guns aren't enjoyable to shoot for many people, and that's before you get into the cost of .454 Casull, or it's .45 Colt as "Specials"
IIRC it was the guy in Texas charged with murder, after he had to shoot someone with a serious case of trail-rage; the prosecutors tried nailing him based on his choice of cartridge, the 10mm. (I can't remember his name now for the life of me, but it was a pretty big deal back then).
Yeah, Harold Fish. I've seen people repeatedly use it as an argument as to why it's bad to carry 10mm because the prosecutor used the caliber as an argument, but the reality is that the judge was an absolute fucking retard and the entire trial was fucked up from top to bottom, and in that circumstance you could have been carrying a J-Frame with wadcutters or some .32 pocket auto and it wouldn't save you.
There's a reason that this ruling was eventually overturned and it ruled a mistrial, but not before the poor guy spent some years behind bars for a crime he didn't commit, and he would pass away a few years after being released.
One of the big reasons why I like 10mm is that is is the most powerful "popular" handgun cartridge that is available in a handgun that is even vaguely concealable. If I could CC a .44 Mag Revolver, or a S&W 500 I would. However, due to the fact that most anything more powerful than 10mm is relegated to massive big bore revolvers, even shoulder holsters under a suit jacket can't conceal them (and I have tried).
Depends a lot on how you dress of course. Smith & Wesson makes the Model 69, which is a five shot revolver in .44 Magnum, and it's a decent bit smaller than the classic Dirty Harry issue. Less long, less tall, less wide.
IIRC the Taurus Tracker was similar in concept, a smaller five shot .44 revolver. Being five shot, the cylinder notches of course fit between the chambers, so there's a certain added strength in that sense, compare to how Ruger offsets the notches on the cylinders of their revolvers to add some strength to their chambers.
For the typical .38 snub that's just a piece of trivia, but for a more compact .44 it may be reassuring, as there's some people who would insist on shit like those +P+ 340gr loads which Buffalo Bore sells, presumably because they got possessed by the holy spirit of Elmer Keith. The gun being lighter would factor for recoil, so you would probably want to get the muzzle ported if you were gonna do that kind of shit.
I'll never forget when some boomer told me a story about a guy who got shot with a 22lr and ran away only to die a few days later cause the bullet got into an artery and slowly made it up to his heart and killed him.
I've heard some bullshit about the .22LR in my life, but that's one which is new to me lmao. Seemingly the mythical rimfire cartridge is not restrained by something as mundane as the laws of physics.
Wasn't there some super-tacticool 10mm pistol shilled by Jeff Cooper that turned out to be a lemon?
Dornaus & Dixon's Bren Ten, as said. The action worked, but they had insisted that the gun be readily convertible to .45 Auto so you can practice with if for cheaper, and their approach to this was to design a magazine which would be for both 10mm Auto and .45 Auto at the same time, and this was something they just never managed to achieve.
They did deliver on preordered guns and all that, but mostly they remained unusable, and they attempted to ameliorate that by providing customers with new and more functional .45 Auto magazines to use with the conversion barrel, but it was too little too late, and the company just kind of fell apart from continued expenses and lack of revenue.
Famously featured in Miami Vice, Sonny Crockett's pistol was actually set up for .45 Auto, which is notable especially because .45 Auto movie blanks could be pretty temperamental in those days, hence why a lot of 1911s in older movies and series were built or caliber converted to 9mm Luger (like in Terminator 2) or outright Spanish Star pistols (like in Pulp Fiction and Magnum P.I).
Presumably Michael Mann decided it was easier to try to deal with .45 blanks that than trying to run 10mm blanks in a pistol which just didn't want to cycle no matter what. They did eventually replace it though.