I own two Stags, this upper and lowers are well made and fit together so nicely. Stag machines their own receivers, they make parts for others as well, so why is some other lower like Spikes, Aero Precision or CMMG etc for instance better than Stag? Every review or article you read about Stag Arms says they pay attention to detail and make good parts. Thanks for your valued input Wanna kill these ads? We can help!