I dunno, I always had heard the threads matched and just the "shoulders" were slightly different, but, in another post here on the Forum a member is having trouble swapping barrels from one .22 to another.......
I just bought a 32 barrel and cylinder from Gallagher on GB for this same project.... I have read they are the same thread pitch and cylinders are supposed to be the same length. I hope so... I guess if it didnt work it wouldn't be the worst thing i've ever spent $100 on.
Well Crud. I removed the barrel from an OM SS this weekend and wouldn't ya know, the threads are way different from the NM SS 32 barrel. The 32 cylinder could be fitted easily enough. The threads are a no-go though..... DANG IT!
I would think the issue is shank diameter, not just a pitch issue. Just looking at my .32 last night, the thread diameter is large enough that it has cut into the top strap. My .22's don't look like that. Ruger and Power Custom use different pawls for the .32 and the .22, though I'm not sure what the difference is.
Yes the firing pin / bushing change out was probably going to be the most time consuming / expensive part of the switcheroo (prior to finding out the threads are different). Oh well.... More to follow.