So what exactly is your point? It isn't legal until you have your tax stamp documentation in hand from the BATFE.
https://www.thetruthaboutguns.com/2015/05/jeremy-s/nfa-for-beginners-form-1-to-manufacture-an-nfa-item/
"As we’ve seen in the whole Sig/SB Tactical pistol brace debacle, *intent* is crucial with the ATF and the NFA. Nothing proves this more than what is referred to as *constructive possession.* Simply put, a violation of the National Firearms Act — in this example, possession of an unregistered NFA item (10 years Federal prison) — doesn’t only happen if you configure an NFA firearm without approval. As far as the ATF is concerned, it happens if you merely possess the parts required to assemble such a firearm prior to Form 1 approval."
My point is once you legally make it no longer "handgun" there is no apparent law against it. So you take your glock17 or whatever tickles your pickle legallyl convert it to an SBR and now you could legally conceal your ____ (insert favorite pistol-rifle conversion here).
My point is the law is ill-conceived and poorly executed. It has no decernable benefits and only hinders the law abiding who can't or won't jump through the useless hoops. Obviously it impeaded you from concealing a weapon in your livingroom when sounds like you would have been more comfortable if you could have.
Look I'll jump through hoops, sit up and beg, rollover, play dead, etc. to keep being able to protect me and my family but when it's so poorly conceived and so **** poorly executed don't expect me not to point it out.