Billet Rifle Systems presented several very neat products at SHOT 2016. Billet Rifle Systems is known for producing billet style, Ar-15 80% lower receivers as well as complete rifles. 80% lower receivers are not considered firearms by the Bureau of Alcohol tobacco and Firearms. To make a functional firearm an end user must mill out the last 20% of the lower receiver.
This year at SHOT, Billet Rifle Systems introduced the BRS-47 Rifle.The BRS-47 is designed to work with the Magpul Ak-47 magazines. It is compatible with any Ar-15 upper that is designed to accommodate Ak-47 Magazines. Billet Rifle Systems is also offering a 7.62×39 Bolt Carrier group that is optimized for use with the Ak-47 7.62×39 magazine. The 7.62×39 bolt is under warranty from Billet Rifle Systems.

BRS-47 Complete rifle. Billet Rifle Systems sells 80% and 100% lower receivers. Billet Rifle Systems can Cerakote these guns any color you want.

Billet Rifle Systems Ar-15 lower receiver for Ak-47 magazines. Contact Billet Rifle System for a list of compatible parts.

Jig for installing a low profile gas block. This jig allows you to knock in your gas tube pin and drill out a retaining pin hole on the barrel. I am going to buy this product.

Packy from Cat Shit One has an Ar-15 that accepts Ak-47 magazines. I believe Packy is rocking a KAC-47. It would be a fun project to build one of these rifles.
A quick note on 80% lower receivers. Most jurisdictions do not require that a finished 80% lower be registered. The Bureau of Alcohol Tobacco and Firearms requires that 80% lowers that are finished have a serial number and transfer through an FFL if they are to be sold.