cylinder compatibility

Question
Can I use a 22wmr cylinder on a Heritage 22lr, 6.5" single action revolver??

Answer
Very simply, NO.

First, the cylinder probably would not fit the frame cut out, and if it did might not function accurately...and if THAT all worked out, the .22 WRM - .22 Magnum round is far more powerful than a .22 LR round, the case diameter is larger, so the .22 LR round has a good chance of splitting when fired, and the Magnum bullet is slightly larger in diameter, so accuracy would not be good.

It's a bad idea all around, and if you already have the cylinder sell it before you are tempted to try it anyway.

Once again, NO...don't do that.