SHS M4/V2 Aluminum Cylinder Head

I gave it 4 stars only because it required some dremeling to bore out the 2 side holes for the notches in the shell, they are too small (G&P M4A1 gearbox). Amazing air seal with ShS cylinder (hard to get in but lube the O-rings and push them in as you are putting the cylinder head in. Also amazing air seal with the ShS M4 nozzle, before lubing the O-ring I could feel the resistance of it dragging. Do not put Teflon on this cylinder head's O-rings.