In general the only difference is that OMs are fluted and NMs are non-fluted with a 22 mag stamping. The new and old model cyls will both work.
001 of an inch and seek one the same length or longer. You would take an overall length measurement of your LR cyl with a dial caliper in. And one too long to fit, as was said above, is simple to 'fit' with a little stoning. Ideally one with minimal play or none at all is preferred. You can always sell it and obtain another. Does your friend's gifted cyl fit in your gun? Even if there is excessive fore and aft play it will still shoot well and safely, it just may 'rattle' a bit. The over all length is the only genuine issue. 22 cyls, I have never had one that didn't time correctly, so that concern borders on the mythical. serial # 150,000 are not considered convertible because they do not yet have the compromise bore size of. Yes, all New model single sixes can use interchangeable cyls, they are all just marked '.22 cal.' except old model 'magnum only' and convertible magnum single sixes marked 'Win.22 RF Mag. I believe you meant something different with your question.
