Did not the 2004 renewal of the AWB that failed left out the granddfather clause?
There were two senate bills, S2109 and S2498: Both would have sunset in 2014. Neither was voted on.
The senate voted 52-47 to extend the AWB as an amendment to the Protection of Lawful Commerce in Arms Act. This energized senator Craig to ask the senate to kill the Protection of Lawful Commerce in Arms Act: This was done.
There were four or five different bills in the house addressing the extension of the AWB and "high capacity ammuntion feeding devices". One of these bills would have extended the AWB forever. None were ever voted on.
Speaker of the house Hastert refused to bring the AWB up for a floor vote. Had the vote been taken it would have passed the house. This would have motivated the US senate to do the same. We owe Hastert.