3D Printer-extraordinaire WarFairy has expanded his P90-styled Charon printable AR-15 lower from a single design into an entire line of printable rifle and pistol lowers.The original Charon receiver design has been upgraded to version 0.2. The updated model features a thicker magazine well with a finger hook (I am sure someone more knowledgable than I can explain in the comments below what finger hooks are for … ).The most exciting new addition to the Charon line is the Carbine, Adjustable Stock. The stock on this model slides out from under the buffer tube to adjust the length of pull. The length of pull is adjustable...