A *long* time ago I filed paperwork to become an official firearms collector in my state of residence. Paperwork finally came through few days back! Huzzah!
For those that aren't up with gun laws, regulated firearms can only be purchased once per 30-days. These are not the federally regulated firearms, such as short-barreled rifles, machine guns, or silencers, but the state ones, such as handguns.
Why should I (and/or you) care? Because parts of firearms that include serial numbers are treated as firearms themselves, and unless its something like a barrel that has it, are treated as handguns due to their size (under X" length). Of note here, is that AR-15 stripped lower receivers, which I'll need to purchase if I want to build another AR, are among those counted as handguns, even though they're literally a chunk of metal that could only hurt someone if you threw it at them.
I absolutely plan on building at least one more AR sometime in the (nearish, I hope) future, and when I put in the order for the lower receiver, I'll order a few, due to the time it takes to get them shipped (anywhere up to 6 months last I checked), and the fact that you never know when these guys are going to be made illegal again. As already purchased and assembled rifles will usually be grandfathered in, I want to have the serialized parts on hand.
So, in summary, I'm quite excited the paperwork finally came through, now I just have to watch my bank account to make sure I don't make too much use of this. *grin*.