Make sure your barrel nut is torqued to spec and make sure your hand guard is not touching your gas block. Your barrel to receiver might not be matched/squared to each other. I lapped my receiver face with Brownell's tool. https://www.brownells.com/tools-cleaning...ping-tool/
The barrel extension (od) to receiver (id) fit is important too. Should be a snug fit not loose.
Check scope mounting also.
The barrel extension (od) to receiver (id) fit is important too. Should be a snug fit not loose.
Check scope mounting also.