If (mis)use of the sig brace is a redesign & NFA violation does it not stnad to reason that misuse of an AR pistol other than it was designed makes it a AOW?
For example, w/ if shouldering a brace is illegal then what about the buffer tube itself?
How about an AK pistol, Per NFA any waeapon other than a handgun that is <26" is an AOW (also knife guns, wallet guns etc) Well if a handgun is defined as "designed as intended to be fire w/ one hand" putting a second hand anywhere other than your strong hand is a "redesign" of the ostensible original intens of the gun.
Hell, what if you grabbed the magazine of an AK pistol (or whatever), you suddenly redesigned the gun into an AOW??
This could be applied to any other type of handgun where you could conceibably make a good off side hand hold anwyere else than on your strong hand, on a fake or real suppressor on a Mac type firearm, below the grip on a glock 18 magazine, on the barrel of a long barreled revolver or Desert Eagle etc. Hell, you could even grab over a non ported pistol slide & fire it, obstructing its function sure, but how would that not be a "redesign."
Sig could sue, but they only have an interest in selling their sig braces... Sure if NFA was overturned they would sell more items currently regulated by NFA, but they dont have a sweet patent on buttstocks which is what everyone would go to if the NFA got pwwwn'd.