Re: 22 revolver cylinder length
The S&W "J" frame is a slightly larger, stronger version of the "I" or .32 cal. design frame, and was designed for the "Chiefs Special" Model which was originally in .38 S&W Special Cal.
I may have answered your other post. If so, again, I opine that their is a slim chance of the possible problems previously mentioned relative to your revolver. Others here have reported that they have done what you propose to do with no problems. However, if someone has a problem by operating their revolver contrary to the manufacturer's instructions or recommendations, I do not want some lawyer to be arguing that I said it was an acceptable practice.
Good luck and be careful.
If you are the member with the H&R, remember that the S&W typically cost 1.6 to 2 times as much as the H&R. For that extra money it should have been built from tougher materials.
Always be careful.