Don’t think this is true unless you can come up with a source for this. As far as I could find gravity is almost negligible effect wise and they usually stop it manually anyways. The only time I’ve heard of this was in the reacher book where he claimed to have such a well oiled revolver he was able to.
That would be a stupid gun design, if an unevenly loaded drum means you can't shoot anymore (or would have to manually align the bullet with the barrel - good luck! Who needs fingers anyway, amirite).
No worries. Wasn't trying to be a dick. Always up for learning something new about interesting things.
I grew up around firearms. Use a .22 revolver as part of varmint management on my little farm. It's a tool not a fetish. (I like all sorts of tools, including firearms.) Lots of myths about guns, for instance: they don't actually increase the size of your penis.