hi
     hoping someone might know why the bolt on a fairly unused norinco ak will no longer stay open on a empty mag.it worked fine until i cleaned it.i know i put it together correctly. any help would be appreciated...
                                                    mark1

They're NOT suppose to stay open on empty mag.  Unless you were using Yugo mag (which has a bolt hold open follower), the bolt shouldn't stay back.  Sometimes they stay back due to friction of bolt riding on top of hammer, but any knock will knock the bolt back home.  Don't put you finger in the action!!

Chances are when you cleaned the rifle, the oil made the action more slick so the bolt doesn't have as much friction riding on the hammer.

I think an ak's bolt only does that while the hammer spring is new and very strong.....the hammer will stick between the carrier and the bolt wich will make it stick back