However, as with any decades-old and heavily accessorized mechanical system, there are custom AR-15 part variations and non-mil-spec components that do not fit together. Be very careful to read ...

How about a cool futuristic-looking furniture set from Hera Arms: Hera USA Hera Arms’ new “close quarter rifle” thumbhole buttstock and foregrip give the average AR-15 a sleek new look.

Using his Stratasys 3D printing machine and blueprints downloaded from the internet, Guslick successfully printed the lower receiver — or frame — of an AR-15 rifle and turned it into a gun.