Hey guys, new to the site. I recently bought myself a new AR15 and I'm having trouble with barrel movement. Took the the gun to the range and couldn't get a group to save my life and after inspecting the rifle I found that there is some slight movement in my barrel. I sent the rifle back to the manufacturer and when I got it back it wasn't fixed! still has movement. I went out and bought myself a multi-tool to check the nut and I was able to take it off by hand using the wrench and just holding the upper receiver in my other hand, but I think these are only torqued at 35ft lbs anyway. I also noticed that the notch in the upper receiver is cut slightly bigger than the dowel in the barrel so you can turn the barrel back and forth a tiny bit even when the nut is tight. Any ideas or advice on what I should do here??? there is some small back and forth movement as well. Thanks