I've not had any issues out of it. I'm getting consistently around 1 inch at 40 yards with it, no leaks or nothing. The magazine does fine for me as well.
If the bolt works out well with the single shot tray, perhaps you can just return the magazine for another one?
if it's still hard with the single shot adapter, then it's a cinch to remove the barrel and clean up the transfer port hole a bit and you should be good to go.
All those who believe in psychokinesis, raise my hand.
Good judgment comes from experience; experience usually comes from bad judgment.