Picked up a generic AK underfolder.  Test firing disclosed the following problem. All directions/locations/et c. are as viewed from the rear of the rifle.

When the bolt comes forward after a shot, the bottom left "corner" of the bolt (about 7 to 8 o'clock) catches on the back edge of the mag's left  feed lip. If the bolt is then manually retracted and released, it will close by spring pressure, stripping and chambering a round. Then you pull the trigger, it ejects the spent cartridge, and again hangs on the feed lip.

Looking into the action, I saw that manually retracting the bolt allowed or caused the bolt to "center" itself so that the bottom of the bolt passed between the feed lips and loaded the rifle. I got the same results with 5 different mags.

I must have fired 80 rounds, of which one was autoloaded. I could not reproduce the malfunction manually cycling the action with a loaded mag.

Any suggestions?

That sucks dude.  I hate to buy a gun that doesn't work as advertised.  My only advize is to send it back to the manufaturer.  BTW, who made your rifle?  Please include what kind of receiver it is with the origin of the parts kit if you know.  I'm planning on purchasing an underfolder very soon and have been looking real hard at the Vectors and Global.

Quoted: That sucks dude.  I hate to buy a gun that doesn't work as advertised.  My only advize is to send it back to the manufaturer.  BTW, who made your rifle?  Please include what kind of receiver it is with the origin of the parts kit if you know.  I'm planning on purchasing an underfolder very soon and have been looking real hard at the Vectors and Global.

It's a home built rifle from a russian surplus parts kit on a Hesse receiver (yeah, I know, but how bad can you screw up a piece of sheet metal?)

Just a SWAG, but I suspect that your mags are being help too high in the mag well, a thicker selector stop under might help. Something could be wrong with the front trunnion postion also. Do you have access to another stamped AK so you can male some general measurements and comparisons ?

Sounds like the mag is inserting up too far (has to go up far enough though or the rounds won't be stripped out of the mag, the bolt could ride over the rear of them) or perhaps is slightly off center or canted to one side.  Could also be something is up with the rails, or the receiver isn't 100% squared/true.

If I'm 100% understanding you the conflict is between the rectangular protrusion on the bottom side of the bolt that pushes the rounds up out of the mag and the leftside feedlip, don't know the particular name of that part of the bolt...  My kit build is doing this a bit too (built from a coldsteel bent blank receiver, everything looks good not sure WTF caused it, blank must be "tweaked" a bit from 100% true) but not enough that it would actually jam it just isn't smooth enough for me and I don't want to eat up any mags.  Mine is the opposite side though, the "right side" opposite the ejector.  I was thinking of removing a bit of the metal on the side of that part fo the bolt that picks up the rounds and is hitting the feedlip.  On this side of the bolt it is clearly not part of what locks up the action and on mine at least removing a little material from where the clearance is an issue doesn't look like it would weaken the bolt at all.  Is that majorly bad juju for some reason I'm not seeing?  The single stack lowcap mag guns have a much thinner part of the bolt there I believe to accomodate the narrower mags (could be mistaken)...  May not be an option for you if it's so bad it totally won't function though, wouldn't want to go too far...