I should say that X frame grips and N frame grips will fit each other. Not exactly the same. K and L frame fit each other as well.
I have noticed that the x grips fit an N frame although the x grip flares out a little more as it approaches the trigger guard and the frame beneath the hammer. So the fit is not completely snug. X grip is definitely a bit beefier and more comfortable.
The analogy is pulling on size 46 waist pants on a 42 inch waist. It'll fit but …...
I haven't tried putting an N frame grip on an X frame so cant comment on whether they fit interchangeably..
Would be nice IMO if someone came up with a larger grip made of space age materials that fit the N-frames perfectly but that did an even better job of absorbing recoil. A "decelerator" equivalent.
