"I doubt that letting go of a few rounds you loaded for your own use"
Probalby true but only from lazyness. Or, you can easily be dead meat for such an infraction of their Regulations.
In a BATF set-up at Ruby Ridge, Idaho, Randy Weaver cut one shotgun barrel a half inch shorter than their rule's limit. Later, while sneaking in to arrest Weaver at his home, the Batmen and FBI teams killed his 12 year old son because they feared the kid and his .22 rifle, and a 28 yeard old hired hand who was with the boy, and then killed his wife who was standing in the door to their home while holding an infant to her chest. And the gov. killers got commendations from their agencies, never heard if that was for their courage or marksmanship.
YOU aren't an illegal alien or other PC protected class so YOU don't get the legal protections they do. Meaning, don't count on the BATF/FBI guys ignoring anything. If they get a burr under their saddle and decide to squash you, they will kill you and everyone around you without batting an eye. And be rewarded for it.