While the amendment process is something we should certainly be vigilant about, it can be a double edged sword. If pro-gun senators want to kill the bill, they could attempt to add an amendment for something like nationwide CC or gutting of the NFA as a "poison pill" that would make the anti-gun senators vote against the bill. The other side did this with the first version of the Lawful Commerce in Arms Act by attempting to add a reinstatement of the '94 AWB at which point the bill was voted down and killed.
Smith, and Wesson, and Me. -H. Callahan
Well waddaya know, one buwwet weft! -E. Fudd
All bad precedents begin as justifiable measures. -J. Caesar