18 USC 921 (a)(16). (A) any firearm (including any firearm with a matchlock, flintlock, percussion cap, or similar type of ignition system) manufactured in or before 1898; and (B) any replica of any firearm described in subparagraph (A) if such replica -- (i) is not designed or redesigned for using rimfire or conventional centerfire fixed ammunition, or (ii) uses rimfire or conventional centerfire fixed ammunition which is no longer manufactured in the United States and which is not readily available in the ordinary channels of commercial trade.
While i'm at it, another nice feature would be for steam to be a unified DRM scheme. Install steam and buy a game and install only the game (and necessary libraries such as XNA for windows). Somewhere along the line I didn't pay enough attention and now I have junk like SecureROM and that Rockstar Social Club crap.
I tried other things and the most useful companion to pencil and paper is a decent camera for taking pictures of diagrams or poor handwriting to be deciphered later. I guess you can just use a smart phone for that now. I also recorded lecture audio but almost never listened to them again. There are the rare occasions where typing on a laptop is better and emacs + org-mode would be my note taker of choice. But yeah, in general, pencil + paper.