Anyone looking for a Spikes Tactical Upper can check here;
http://www.joeboboutfitters.com/Spike_s_Tactical_Upper_Receiver_M4_Flat_Top_p/sp-sft50m4.htm
http://www.joeboboutfitters.com/Spike_s_Tactical_Upper_Receiver_M4_Flat_Top_p/sp-sft50m4.htm