There's a Schneier post about this from 2009: http://www.schneier.com/blog/archives/2009/04/definition_of_w.html http://www.schneier.com/blog/archives/2009/04/

There's a Schneier post about this from 2009: http://www.schneier.com/blog/archives/2009/04/definition_of_w.html http://www.schneier.com/blog/archives/2009/04/definition_of_... Here's the legal code which describes a "destructive device" (passed in 1968 and amended several times): http://www.law.cornell.edu/uscode/text/18/921 http://www.law.cornell.edu/uscode/text/18/921 Note that it is so broadly written that it has to specifically exclude antique muzzle-loading rifles.