Great lightweight pistol/sbr upper - Spikes Tactical Carbine Cold Hammer Forged 11.5in Upper Receiver

The upper in the picture with the BAR2 quad rail was the upper I ordered but I received the upper with the CRR quad rail which is a newer lightweight quad rail. Not complaining due to how lightweight it is. I have put 350 rounds through this upper with standard carbine buffer and H2 buffer and it has been 100% reliable so far. Accuracy with the CHF FN barrel is as expected. I just ran a red dot and was hitting steel out to 325 yards with M193 and m855 so it was accurate enough for its intended purpose as a home defense gun. I may lower the buffer weight to a H buffer as it’s getting broke in it doesn’t seem to need the H2 buffer like it did when brand new. Only issue is the sides of the holes where the takedown and pivot pins go through seem to be over spec. A hair too wide cause I could not get the upper to fit any over my 6 lowers. Slightly filed the sides down and refinished them where I filed and it fits tight with no wobble. So It was an easy fix.