jcelect, I took a look at mine and it is about half way between the two photos. Obviously some erosion but the barrel actually looks pretty good once you get passed the first eight of an inch. So far, I have tried four powders: IMR4227, H110, 2400 and HS6. I can get a 2inch group off a bench at 25 with one of the IMR4227 loads and according to my notes there were no problems with the cylinder or ejection. With the other powders, everything was ok as long as the velocity was down around 1200 to 1400 fps. Above that and I started to have problems. 2400 obviously produces the most pressure and I won't be using that one again for the Jet. I guess the answer to my question is to be satisfied with less than the factory ballistics. It is still a really fun gun to shoot.
I do have the inserts that will allow me shoot Long Rifles but the accuracy isn't good and loading and unloading is a PITA. Maybe I will look into getting a new cylinder from S&W in .22 LR. But, I have a really nice Colt Officers Model Target in that Caliber so don't really know if I need two. Have to think about that one.