In theory, since a movie is just a series of still frames, the same techniques could be used to modify individual frames as are used to "photoshop" a still image, (albeit, tediously). You might find the tools and tutorials at this site of some help in analyzing individual frames: http://fotoforensics.com/
You might also find some of the information at the associated Hacker Factor blog of use: http://www.hackerfactor.com/blog/index.php?/categories/17-FotoForensics
With this logic applied, beleaguered industries worldwide can gain instant relief! Just think, of it. For an example, when you fill the tank or change the oil of your car, you'll owe the manufacturer for your *new* vehicle!
Remind me again how Circuit Court judges are selected.
The first point was that the initial adoption of pistols was primarily by outlaws, while the cavalry examples you cite were later developments.
The rifle was, for example, developed for the hunting of game. It's use in a military capacity had to wait until the advent of the American Revolution.
So your defense is that any target practice validates a weapon as not intended to kill humans? If then, we use Sarin to kill some gophers, is it henceforth alright to use it on people?
"The fundamental principle of science, the definition almost, is this: the sole test of the validity of any idea is experiment." -- Richard P. Feynman