Well, I have done my 2 AR builds. Number one, Model 1 sales parts kits 16" heavy barrel upper, Magpul ACS stock. Eotech 512 and UTG carbine Quad rail, no name foregrip, essential arms lower Number 2 DSA 16" parkerized M4 upper, UTG extended Quad rail, DPMS lower parts kit, standard stock. Essential Arms lower. I haven't decided on an optic for #2 yet. cant decide between eotech or aimpoint Sorry, posted wrong link Wanna kill these ads? We can help!