Aero 9" quad rail - Aero Precision AR15 Gen 2 Enhanced Quad Rail Handguard

Overall Aero makes nice Equipment. I have the 15, 12 and now a 9 inch model. Goes great with the M4E1 upper or any upper for that matter if you get the corresponding barrel nut (10-20 bucks extra) the one thing I have noticed is there is some play well slop in the guard when you first install prior to tightening up to the reciever (M4E1 that does not use standard barrel nut) generally I sight in these with a 1/3rd co-witness red dot then loosen the guard as to get a better sight alignment with the backup's and use blue loctite to secure in the screws. Initially prior to figuring this out my rear backup sight was almost maxed out to the left. Like I said these have a significant amount of play until you get them tightened up and secure. Also recommend getting upgraded Steel screws to replace the ones it comes with as they will strip out easily especially if you loctite them, Ebay for $6 a bag of 20 or your fav hardware store.