Cuz milsurpyness is a twilight zone that cannot be explained. At least with milsurps some of the value is predicated upon relative scarcity and so on and isn't entirely effluvial fluff, like it is with a lot of other collectible guns.
-Mike
This, and really if you look at a sks , ask yourself how much would that thing cost if made today.?
For 350$ in the milsurp area K31 all day. Super nice 2 stage trigger ,accurate, easy to reload for ammo is cheap and very good .....at least at the moment.