Purchased a Diamondhead Handguard for my Aero Build and after getting everything together found I had a very very minor alignment issue. Called Aero customer support explained what what was going on and that I wasn't sure if it was the rail or the upper receiver being out of spec. No questions asked he immediately stated to just send it in and they would send me a replacement under warranty no problem.
1 week later the replacement arrived, installed it on the rifle and the alignment is 100% perfect. Outstanding customer support and thrilled with the new rail!
Two Thumbs up for Diamondhead!