Not too wacky of a mod. But I have a rule of thumb: never build custom what is already produced and is obtainable. You may agree once you read further and see what's involved and really spin those wheels spin.
Yes all the parts you mention will interchange with some fitting. However the greatest challenge will be converting the frame to rimfire, so I'll start with that.
The hammer nose (firing pin) and it's associated hole in the frame must be raised for .22 rimfire and there's 2 options:
1. Replace hammer with a Model 53 dual firing pin style or .22 rimfire hammer. Re-drill firing pin hole in hammer channel higher to accept a frame mounted firing pin (from the front before barrel installation). Leave original bushing in place. Re-counter bore hole in frame for firing pin bushing. Install rimfire firing pin, spring, and bushing.
Model 53 dual firing pin hammer and frame:
http://smith-wessonforum.com/s-w-re...-53-remington-jet-question.html#post138029843
Photo credit: Donald Paul
Photo credit: Donald Paul
2. Last and simplest option is to modify existing hammer nose to raise firing pin tip: Tig weld retaining rivet hole and re-drill lower to raise the firing pin tip. Relieve top of hammer channel to clear the higher hammer nose. File top of hammer nose flush to the top of hammer. Re-heat treat hammer nose.
Re-counter bore and relocate firing pin bushing to raise firing pin hole, and re-drill hole in hammer channel (from the front before barrel installation).
The potential areas that might need fitting:
1. If refinishing is not going to be required, you're better off using the original yoke; the front of the new yoke is not going to match and be flush with the front of the frame.
2. The hand/cyl extractor star: if timing is not right, try the extractor star from the original 38 cyl. Depending on the different vintages of the two cyls, that may not work if the extractor alignment pins do not match up. If that's the case, and new cyl doesn't "carry up" (rotate far enough for it to lock up by the time the hammer cocks), the hand is too short, so replace it. If hand rotates the cyl too far and it locks up before the hammer cocks, hand is too long and must be fitted (shortened).
3. Cyl end play: if the original yoke is used with new cyl and there's end play use shims in rear of cyl axis center hole. If cyl won't close, fit (shorten) the rear end of the yoke axis tube.
4. Cyl/barrel gap is preferred in the .004" to .008" range: if too tight stone the end of the barrel to open the gap. If gap is too large barrel must be set back one full turn and gap adjusted. Correct cyl end play first if any.
5. Barrel/Extractor rod knob: if both barrels use the came straight rod, no problem. Check/fit the rod and ctr pin to the new barrel lug. Especially if barrel had to be set back. If using pre war parts which have notched barrels for rods with knobs, the rods are all right hand threaded. So the cyl extractor star will need to be prior to ~ 1960 to have right hand threads on K and N frames.
Hope that helps
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