Just got back from the range from earlier today with my brand new in box Windham AR-15.
It was very disappointing at first. The removable carry handle / sights were improperly drilled and would not attach evenly to the main rail. (Sat at an angle) This caused me to have to drift the rear sight almost all the way left in order to achieve a proper 25 yard zero.
After having my buddy also shoot the rifle we were able to diagnose the problem.
Problems aside I was able to remove the carry handle sights and swap on my buddies Magpul flip ups and zero the rifle within the next 10 rounds... Awesome! Shot around 50-75 rounds flawlessly through the rifle and it feels great.
I returned with my AR to One Shot Cincinnati and they came to the same conclusion but were very helpful. They took down my info once again, removed my carry handle and said they would inform me when they receive a new one.
**One Shot Cincinnati also loaned me an Eotech 552 so I could get some range time in while I wait. They are an awesome store!
TLDR: Went to range, improper fit carry handle/rear sights. Store sending me new ones/loaned me Eotech.