I never quite understood the desire to have "one of everything" in their collection. Pretty much impossible to do unless you have unlimited money resources.
I accumulate guns I have an interest in, not to "fill a hole".
I have no liking or use for much of any communist-block weapons, so I don't own any. Mosins, AK's? What's the point?
Then again, most everybody here probably thinks I'm an idiot.
Collect what you like.