I'll start by pointing out I own more .357 sixguns than any other kind of gun, including autoloading pistols.
That said, I also spend a lot of my shooting time in "action" competitions like USPSA and to a lesser extent, IDPA and ICORE. I finished fourth overall in an eight-stage, 96-round "carry gun" match behind three Glocks and ahead of thirty other shooters, and I'm "B-Revolver" in USPSA. So I do have a some minimal level of handiness with the revolver.
No, cardboard sports are not related to gunfighting. The only things they can provide are:
A level of stress in shooting nearly all of us can't get practically anywhere else;
And a hard-numbers, real-world answer to how fast you really can place bullets in specific target areas, under that certain amount of pressure, and in certain varying degrees of physical limitations such as awkward angles and in motion.
I don't shoot .357 in competition because after that first shot, it's not a good fighting caliber. Don't take my word for it. Go to a cardboard match with a .357 and see for yourself. I did, a number of times. My scores drop like a rock. Not just for a 26-round course; for a six-round stage, too.
As a result, a .45ACP revolver is about the only sixgun I'd say is good for fighting with.
I have an excellent Detective Special filled with Buffalo Bore semi-wadcutters that I shoot a lot, have some decent skill with, and it might be okay against a lone opponent, and is sure more practical than a Mountain Gun or New Service. So it gets used when I leave my home state sometimes.
But the .357's blast and recoil are a big problem when you're in a hurry.
I've been to an LEO training officer-friend's office and looked through his large real-world video collection of active shootings.
I can't say, after having seen all this mayhem, that six rounds is a comfortable number. Especially nowadays in this era of drug-addled attackers who feel little or no shock or pain from a good hit.
Another good friend of mine watched as his partner put six high-performance .357 slugs into the torso of a drug-crazed lunatic attempting to behead my friend. They never even slowed the guy down and my friend nearly died. Several officers were injured taking down the guy with the six slugs in his guts and chest.
Both my friend and his partner went out and bought hi-cap autos as soon thereafter as they could. Bobby never carried a sixgun again in the line of duty.
I must reject any suggestion that limiting one's ammunition capacity is tied to better training or marksmanship.
I love my sixguns and shoot the dickens out of them, but I have no illusion that I'm better off with six .38s than nine .45s on board.
I will defer on one point to kraigwy- in certain rural applications, I, too, would want a Model 28 for its penetration and possibly greater effective range over the .45ACP.
Close up, fast, adrenaline going, it's a 1911 for me.
The timer and targets tell the tale.