This identifies the bolt camming surfaces and a potential problem with current imports.
Clicking the picture below will open a new window. I am doing it this way as I've had requests for this sort of thing on several forums.
My previous videos were mostly text and pics – slideshows – but I decided to set a camera on the drill press and do this live.
There are various theories flying around about why the Mosin's bolt closes fully when only in partial battery. It's simply to keep the bolt from being open enough to become a projectile.
It is not, as some speculate, a decocker of any sort.
I hope someone finds this useful!