Zeus Arms "ARTEMIS" AR-15 Lower Receiver. The Artemis series lower is cut from a solid block of 7075 Aluminum. It also shows no visible markings on the sides of the receiver maximizing the amount of space for customization. All of our lowers feature a more aggressive magwell flare and a upper retention threaded hole. a 7075-T6 aluminum a Precision Machined Magazine Well a Accepts all mil-spec components a Upper Retention Threads Built in so you can always get a snug fitment