A friend has this same problem and he replaced the firing pin. He did it himself and said it was a real tough job. he is not a gunsmith, just average guy. From what he said, sounds like he had heard of it also happen to another friend. So; while not common, it apparently does happen that the firing pin is just to short? I could give him a call and ask, that is the general idea what he told me.

Actually, it could be the chamber as stated above, but a workable fix was a new firing pin. I think his was a cf rifle.

now, NEF is part of Remington and I guess service really stinks. But, his gun was not from Remington anyway, as far as I know. The Remington/NEF had other problems, like scope rail popping off. And they dont like to talk on the telephone. probably not about to service the NEF guns. And if they did it could take months. Your are from Australia, so maybe not relevant I live just down from the old NEF (H&R) factory. You could walk right in the door and ask them to build a gun.

Hope this helps, ... If I see him, I will ask again. I dont think it was the transfer bar. Now, I wish I payed better attention.