Hello Again Murdock :
I just read your posting in the "For Sale" section of these pages and noted more fully what you are desiring to do. Now that I am up to speed here, let me comment on the proposal to install a Numrich Arms 22 Rim Fire barrel on a M-44 J,.Stevens action.
The 22 R.F. Numrich barrels are for fitting up to the M-1915 J. Stevens "Favorite" actions, not the M-44 action that you have. If you want 22 R.F. for that action, which I consider an excellent choice, it would be best to search out and purchase a M-44 barrel of either central fire or rim fire (either will work) and send it out to be re-lined in the 22 R.F. cartridge and re-chambered to that cartridge. These barrels do become available, but you must be willing to except the fact that it won't happen instantaneously, but it can and will happen.
Also, be aware that if you find a M-44 barrel tomorrow, there is no guarantee that it will screw right on your M-44 action and index right up at 12:00 o'clock with the extractor cut exactly at 6:00 O'clock. (yes, the threads are the same) Each barrel was fitted by hand, thus you will be faced with the result of that in order to get it fitted to your action. Please also be aware, that the early M-44 actions were fitted with 7:00 O'clock extractors which I would try to avoid in favor of the later 6:00 O'clock position.
One last point, and you should feel free to get back with me later if you feel I can be of further help; not all breech blocks fit with all extractors. The milled slot in the block must match the width of the extractor, . . . .not a big deal, just a point of information I would want you to have as you go through this project.
My regards,
Creedmoormatch