This Answers A Few Questions

 Early reports were that FBI refused to allow BATF to examine the rifles used in the 2017 Las Vegas Massacre.   Here is the ATF PowerPoint slide:

A troublemaker filed some FOIA requests on that disaster.

 The initial report is dated Oct. 2, 2017 and includes the claim that the murderer "illegally possessed prohibited firearms in violation of 26 U.S.C 5841."  That section is the NFA weapons section.  If bump stocks were not machine guns yet, how does this make sense?  Since the FBI did not allow BATF to examine the weapons, this just gets curiouser and curiouser.  The guy had money.  He might well have had someone make machine guns.

Of course, the FBI could not be hiding something.  They are paragons of integrity.