A while back I ran into a cartoon series drawn by a lawyer. In it he explains the law in ways I can understand. This page discusses "Mens Rea", or "a guilty mind".
http://thecriminallawyer.tumblr.com/post/14597572112/6-mens-rea-i-didnt-mean-toThe whole series is a fun and informative read and you can start at the beginning by clicking here:
http://thecriminallawyer.tumblr.com/post/13656784545/1-introduction-crimeI mention this because while I was reading about David Olofson I became aware that the government was deliberately avoiding Mens Rea. It didn't matter to them that he did not deliberately modify the weapon, and the AFT even had to jury rig it to get it to fire 3 or 4 shots before always jamming. Knowing this they deliberately prosecuted him anyway to make an example of him. It is also obvious that the court was jury rigged to convict him since the judge wouldn't allow the manufacturing documentation that proved he didn't modify the weapon by claiming it was a "tax document".
Specifically, the artist, a lawyer named Nathanial Burney, mentions Mens Rea and Actus Rea in explaining how the court would not convict a man they way they convicted Olofson:
http://thecriminallawyer.tumblr.com/post/16202923895/interlude-the-juryThey made an example, alright, but the example was of how a government bureaucracy can become abusive, or even tyrannical.