That only works if both surfaces are polished and very, very flat, like gauge blocks. If you have a film of lubricant, dissimilar surfaces, or small contact points, then that’s not really an issue. Surfaces that have been Parkerized, for instance (which, IIRC, is a form of oxidation, and is a common finish on firearms) are quite rough, and should not freeze weld together. Similarly, a typical mill finish also won’t behave like that.
In the vacuum of space, the metal in the gun will freeze weld together; there won’t be any mechanism movement.
That only works if both surfaces are polished and very, very flat, like gauge blocks. If you have a film of lubricant, dissimilar surfaces, or small contact points, then that’s not really an issue. Surfaces that have been Parkerized, for instance (which, IIRC, is a form of oxidation, and is a common finish on firearms) are quite rough, and should not freeze weld together. Similarly, a typical mill finish also won’t behave like that.