"I see no evidence that the ATF changed their interpretation. So far no one as said that EP Armor submitted a lower to the ATF, the ATF declared that lower not a firearm, and then at a later date changed their mind and declare that lower a firearm. All indications are that EP never bothered to submit a sample and instead started manufacturing something that they thought was not a firearm."
Really? I was under the impression (and have read second hand*) that EP did in fact have an approval letter. Which would make sense in light of their other (rejected) determination letter --they obviously conversed with the ATF Tech Branch in this manner. The ATF alleges --with tenuous arguments at best-- that EP changed their process so it was no longer consistent with that prior approval, and thus it was no longer applicable, and that part of that new process involved creating a legal firearm. ATF also alleges they do not know when the change occurred, or if they issued the initial approval as part of a misunderstanding of EP's process in the first place, and EP alleges the ATF is now willfully misunderstanding the actual and approved process (ostensibly to shut them down).
"I think there is a very good chance that some people here who think they know what the ATF is doing and why they are doing it have never worked for any government agency."
Yup. Lots of folks here attributing conspiratorial competence to, or putting faith in these agencies which deserve neither. I fully expect all (not "most") ATF agents are as confused about this as we are, and try to go about their nebulous jobs in the ways that are least likely to get them fired/reprimanded. Not surprisingly, this is not sufficient for a system to be well managed and effective.
"By that argument, isn't every block of aluminum that's maybe a foot long by three inches square also a firearm? What if someone takes such a block of aluminum and grinds it more and more to the shape of a lower receiver? When does it morph from a block of aluminum into a "firearm?"
That's what the issue is here.
There needs to be a solid definition of what is a firearm and what is not. Just allowing a government agency to arbitrarily keep redefining that sets a bad precedent."
It goes to even baser principles than this. I submit there cannot be a solid definition of a firearm so long as the practice of prosecuting adjacent objects goes on. Think about it; whatever the ATF defines as a firearm, once step adjacent to it is 'readily convertible' and therefore a firearm, as is the item next to it, therefore, and so on it goes. Each step takes time and paperwork and is logically harder to defend as a 'functional gun,' but the progression is inevitable. The law of precedent only works to further increase restriction, it cannot reverse itself without outside action (courts).
To me, the only way to remedy the obvious separation of powers issues that is the ATF, is to split the determination/categorization function from the enforcement mechanism. That way, while you still don't have congress writing the law (as would be desired, but which is impractical for technical/detailed matters), you at least don't have the cops writing the law at the same time they enforce it (the very definition of law-enforcement corruption, by the way). Find some way to force these two independent groups to have crossed motives as well as some checks and balances, and you have the potential for an intelligently run system.
TCB