I have a K-22 dad bought in about 1971. I had a couple single action 22s about then I shot a lot but also shot the K-22 a LOT as a kid. All the odd jobs, farm work, yard work or whatever, Id buy 22 ammo. Normal outings were 500 rds whenever I could go. The family had a place out of town along a river with woods around it, so always had an easy place to shoot. I started riding motorcycles on the street when i was about 13, (no drivers license). if I couldnt find anyone else to go id take the K-22 in a day pack and go by myself. Local gun shop guy let me buy ammo being under age as he knew the family and we did business with them. I shot scads for fun and hunted squirrels with the K-22 many times. Dad either gave the K-22 to me or I traded him out of it when I moved to Az in 81 and I shot it a LOT there also. Normal was 500-1000 rds per outing. Im certain something over 200K rounds through it, possibly closer to 300K. Its a little looser than the average K-22, but still functions and times fine. The only work thats been done was replace the screw that holds the thumb piece on when it fell off and was lost. I may see if I have another locking bolt that might snug it up a little.
Dad also had a model 19 Smith 4" he bought about the same time. Local shop had commercial 38 wadcutter reloads pretty reasonable, I shot the model 19 a fair bit, and later traded dad out of it and it went to Az with me. I carried it some, but not a lot. I dont know how many rounds through it, not huge amounts, maybe 500 magnums, and many times that in 38s. Still have it, swapped a 6" then a 2 1/2" barrel onto it, I think the 6 will end up back on it soon as I have another 2 1/2" factory gun with round butt for carry now.
I bought a new model 29 in about 1982. I carried it pretty much daily open in Az riding motorcycles, roaming the hills, rural living, and shooting a fair amount, then after I moved north to grizzly country, where it stayed my main daily carry gun for dog walks or up here the bears live. I semi-retired it a few years ago for daily stuff, it still goes when I get up where the bears live full time, but I dont do that as much now. I shot a deer a couple-few coyotes and a bunch of bunnies and jacks with it. Best shot was a coyote at a bit over 200 yards near Flagstaff, 1st round hit.
The deer with the 29, about 1983
About average results shooting the K-22 kneeling at 25 yards. I never tried to figure out if one particular ammo shot better than others, I mainly bought cheap, the old Winchester Wildcat stuff ran reliably, if a bit waxy, but was cheap and widely available in the day.