I am thinking about threaded (little longer for higher velocity, and potentially - for a can) barrel and recoil spring for my G19/5.
So, I wonder is someone has personal experience with such conversion.

No, i rock the original tcm in the 1911 and love the caliber.

Its my understanding that the later "9r" cartridge was made because they couldn't get the oal and bullet shape of the standard tcm to run right in the glock conversions. Have you run into any issues finding the ammo?

I stocked up back when the $319 cases of tcm ammo were plentiful at ammosupplywarehouse and they sold the boxes of 5000 oem 40gr bullets for $109 for reloading, but have never seen the 39gr "9r" bullets offered.

I hope not, but it seems like the tcm is dying out, and the 9r never quite took hold.

Thank you, Jason!
I see both .22TCM and .22TCM9R available online for $20-$25 per 50 rds.
I also see that conversion kits for Glock 19 are not widely available and might be not reliable for self-defense.
This is why I would like to hear from first-hand experience.
Unfortunately, I am not a big fan of 1911 platform due to its various reliability issues. Yes, some say that it can be tuned, but my belief is the self-defense gun must be 100% reliable right out of the box.
I like 1911s esthetically, though, and they surely are fun to plink with.

An advantage for the M1911A2 .22TCM pistol is convertibility. The kit comes with two 17 round magazines, an extra barrel in 9mm Luger, and heavier spring for 9mm. The mags work for .22TCM and 9mm. So, if the .22TCM spring or barrel fail or there is a lack of .22TCM ammo, the platform becomes 9mm.

The penetration of .22TCM is quite impressive (starts at 3:00)!