Some technologies should be illegal.
I’m not going to link to it, but YouTube just recommended a video about the DesertTech Quattro-15, which allows an AR-15 to take 53-round magazines.
As a reminder, civilized states limit you to 10-round magazines because they know that there is little defensive use to more rounds but much offensive use.
So don’t worry if you forget the name: you can be sure it’ll get coverage when it’s used for the next mass murder.