I received this upper in less than 10 days and finally got it out to the range. It is on a Windham Weaponry lower and fit better than my stock upper. Matches Magpul FDE 100%. Took 4 rounds to sight in with a Leupold 1.5x4 AR Scope and I am able to get tighter groups with this at 100yrds than my original 5.56 upper. Thank you Ghost Rifles / Grid Defense!