Once you've commented please hit up your congressional delegation too and tell them to write a letter to ATF demanding a full comment period for this regulation.
Remember in 2008, it was only one congressional letter which re-opened the closed comment period for the NPS self defense ban http://edocket.access.gpo.gov/2008/E8-15614.htm
Remember the comment period closed and we had easily won. At that point we were up 3 to 1 for our side. Then, one gun hating US Representative got NPS to "re-open" the comment period.
This is no different. Have them write a letter demanding ATF open the regulation for a full comment period, or withdraw it.
Very short, very simple.