Three years ago I bought a 4" 17-6 (full lug) for $185 plus tax. Mint, No box. Came out of a high-traffic Gunshop in Vermont and the seller thanked me for taking it off his hands.
About the same time I picked up a 17-5 (heavy barrel, no lug) for $325. Again, Mint, No Box.
Last fall I was offered another 17-6, perhaps unfired, correct, with box and papers. The seller wanted $600. I counter offered $475 but he dug in his heels at $550 and I passed. It seems that he had just picked it up at a large nation auction (Amoskeag, I think) and had paid $550 plus the premium. Later he discovered his error and just wanted to get out from under.... he left the gun in the shop on consignment for a while, but last I heard he had taken it home.... I have no regrets. Bet he does.
Lest you think I am a cheap skate, not long ago I happily plunked down $1000 for a mint 17-No Dash with the correct box from 1961 (as I recall) and was glad to do it....
The thing that I have found about K-22's and those that seek them is that it's the 'classic' years from 1948-68 that sell well and are in the most demand.... While it's true that the later, modern K-22's (17-5's and later) were not made in large quantities, it's also true that there isn't a line around the block to buy them either... even -4's seem to suffer this fate.... I had a fella here not long ago that begged me to take his mint in the box -4 off his hands because no one else was buying.... I already had two, one in the box, so I had to say no.... his last price was $425....
The -5 models and later K-22's are really the 'Dead End Kids' of K-22's.
So When It Gets Right Down To The Nut Cutting, folks can ask huge prices for these things, but like the seller in the fishy auction noted, I doubt that they really sell well.... at least in the circles I travel.
As far as field use, I'd much rather take out one of the 18's or Pre-18's that are lighter, easier to holster and just as useful.
On the other hand, short barreled fighting magnums like the 3" 66-2,-3's are always in demand. Prices can be shocking for examples in only average, issued condition.... those in excellent condition are right up there with or surpass 3 1/2" 27's and are second only to the 3" 19's....
So...... My Two Cents...... If the trade were offered me, I would not let go of a 3" 66-2 or -3 for a 4" 17-6 with the underlug.
Drew