I had to look up the TCM....cool and all...but what's the advantage? Looks like 38 super carries significantly more energy out of a 5" pistol?
Made from 223 brass, which I will never run out of. Factory TCM brass is not that great. Works at 223 pressures in a Contender, not sure what pressures Armscor is loading to for normal pistol use. Out of a 13" Contender, no appreciable recoil making it a fun range toy at 100 or 200. That's also because MGM makes really nice barrels for the Contender. Runs 45 to 55 grainers at 2400-2500, Lil Gun is a hell of a powder, and my favorite so far.
Huge selection of medium to small game bullets in 223, and appropriate powders, and multiple choices in brass. I'm nowhere near figuring out what it likes best yet. That said, there is virtually no factory load data out there and isn't likely to be unless SAAMI adds it to the list. QuickLOAD and anecdotal load data is really all there is.
Certainly not a cartridge that everyone is going to have fun with. I got into it after a conversation with an EPO out my way, who maintained that chambered no larger than 38 caliber meant no larger than the 38 special in a pistol. While driving home, I started thinking about what an ideal night coyote pistol cartridge would be based on his interpretation of the regs. The simple answer was running 38 specials in the 357 Mag Contender barrel I already owned, loaded to the pressures the Contender was capable of instead of catering to all those revolvers in 38 made since 1895. Not the technically ideal coyote cartridge because of bullet selection in 38 (but certainly would have been effective anyway), so I started looking at wildcats. Rimmed cases are easiest in a Contender, so what I was picturing was a 38 special necked down to 223. At some point while looking for that, I stumbled across the 22 TCM, which had advantages because of being commercially produced like dies that were already in catalogs. Ordered the barrel from MGM, and have been playing with it on and off ever since.
Summing up, not a good cartridge if the only part that interests you is the shoot the coyote part at the end. There are much better choices for that. But if seemingly endless load development possibilities (with no industry safety net) sounds like a good time by itself, it's an excellent cartridge and easier to get into than most true wildcats. I suppose the next step for mine is deciding to spend on thermal for it.