If the ATF lawyers thought they could do that, they would have by now. They have dropped criminal cases and let people go over this issue, which you just know had to hurt their little black hearts.
There is no part (singular, as the definition is clearly singular) on many modern firearms that fits the legal definition of "receiver". It will take legislative action to change that definition. Those are facts. That can't be reinterpreted.
I don't disagree that it
shouldn't be reinterpreted, but I lack your confidence in ATF's honesty, integrity, and good faith. I also agree that they've made the tactical decision to suspend trials to avoid a decision going against them. In another venue or with a different administration in place, I could easily see them arguing differently. Remember, they made their move against bumpstocks the moment they had presidential support, and there was no trial necessary, nor requirement to argue the point in front of a judge.
Except that, as the ATF said in that very same ruling, unlike a bump stock a belt loop does not meet the definition of machine gun. Read the definition and see if you can figure out why. And why the stock is a machine gun and the belt loop is not, without rewriting law.
Of course the belt loop is not a machine gun, and to give the devil his due, yes there are differences in a stock (both intent and the fact that it is affixed to the gun). That said, I still maintain that the mental gymnastics you are enthusiastically entertaining to try to define a bumpstock such that it is a machine gun require certainly no more flexibility than saying that a part may be separable into component pieces.
The only way the ATF position on bumpstocks (and your defense thereof) is justifiable is if the stock automatically tripped the trigger when retracted. Since it does not, and since the shooter's finger must pull the trigger, the rest of the arguments about the foregrip and the pistol grip and the pushing and pulling actions somehow forming a trigger just don't hold up to scrutiny because those actions don't actually cause the gun to fire absent the finger on the trigger. If you were to grab hold of the stock and foregrip and yank any way you like but keep your finger away from the trigger (or auxiliary sear, if you'd prefer), no shot can be fired.
