A ruling has finally been issued in the long running case of the model rocketry community vs. the BATFE and the BATFE lost, badly. If you read the article, “APCP” is “ammonium perchlorate composite propellant” which is the standard solid fuel used in larger model rockets. The BATFE claimed it was an explosive and regulated it as such, despite it being, in fact, not an explosive1. The judge basically acknowledges this in his ruling, along with the BATFE being jerks about the entire matter in taking the attitude “we’re the BATFE — we don’t have to explain anything, even to a judge”.
The model rocketry community is in favor of reasonable regulation, i.e. we don’t think being able to store hundreds of pounds of APCP in your basement is a good idea. But the idea that 62.5 grams of it in one grain is a hazard on the order of dynamite, but two 50 gram grains have no need of regulation, was just ludicrous. As far as I know, under the current regulations, you can in fact store hundreds of pounds of APCP anywhere you like as long as you do it in chunks of 62.5 grams or less. I favor a “total mass” regulation with some reasonable value (say, 25-50 kg). Under the limit, do what you like. Above the limit, you need to start taking standard precautions appropriate to high energy flammables. But I don’t expect the BATFE to see it that way.
1 For the hard core geeks, an explosive is defined as a substance with a rate of chemical reaction that is faster than the speed of sound in that substance. If the rate is rapid but slower than the speed of sound then it “deflagrates”. APCP deflagrates, it does not explode.