from what I remember, these months of planning and execution [pun intended] resulted from BATFags entrappment over 2 shotguns cut down to 17 & 1/2 inches.
My take is that Mr. Weaver must have REALLY p!zzed somebody off to draw that kind of concentrated effort from a whole army of alphabet soup... my .02
I vaguely remember that they were trying to nail him so they could force him to roll over on someone else.
I think it might have been related to PROMIS and INSLAW.