I finally finished my HD rifle build. The upper is an Aero Precision with 16 inch Ballistic Advantage Hanson Barrel (5.56), Midwest Industries lightweight handguard, and generic A2 flash hider. The lower is an Aero Precision M4E1 Enhanced with 2 stage Geissele SSA-E trigger, Geissele parts kit, BCM grip, and Mission First Tactical butt stock. The sighting system is a Holosun HS510C with Magpul MBUS backup sights. The weapon light is a Streamlight ProTac Rail Mount 1. In retrospect, I probably should have gone with a single stage trigger. For home defense, faster reset is more important than precision. I'll probably swap the trigger out later. I really like the 6 o'clock light mount. I know it's not super fashionable these days, but it works for me. The light is far enough forward that I don't get any barrel shadow, and shooting around obstacles (e.g. doorways) is more important for my application than shooting over barricades.