See if you can clean the trigger unit....sometimes they get caked up with old oil & dirt and things don't seat the way they should.
Nice job getting your old childhood Daisy up and running again. Its nice when you can do the work yourself and see the transformation before your eyes. It really sounds like its accurate too from that 10 yard test group. That's extremely solid for bbs. Slap a scope on it and you are going to have yourself a match gun!