New build problems

[LarryD]

Hey guys, I am a new poster here but I have been lurking for quite a while and I have learned a lot just by reading the informative posts. I am having a problem with one of my builds and I wanted to see I someone could help out.
On my newest build I am using a Sabre Defense 14.5" mid-length barrel, M4 style upper receiver, Larue low profile gas block, a 10" Daniel Defense Lite rail and Troy flip up sights. When I put everything together I noticed that the barrel was offset to one side in the end of the rail. It's actually .050" offset to one side. I took everthing apart and examined everthing to see if I could determine the problem. It appears that the barrel extension is loose in the upper receiver and does not "seat" correctly. How tightly should the extension fit in the upper?
I have a new upper on order from Bravo Co. (just got the notification as I am typing this - great guys!) so I will see if that solves the problem. I have installed several DD rails, both Omega and Lite and I pretty sure I am doing evertyhing correctly. I just wanted to see if you guys had some tips or suggestions.
On another note, I e-mailed Daniel Defense about the problems I was having. I am not blaming DD one bit as they make excellent products and just wanted some help. John Holland responded and said they would replace the rail system at no charge or I could send them my upper and they would install the rail for me at no charge to me. That is really going above and beyond excellent customer service!

[spamsammich]

all of the uppers I've built have had pretty tight barrel extension/receiver fit. Most of them needed to be seated fully with the barrel nut and once in place, were locked up almost solid. My latest build with a Noveske barrel and Rainier Arms upper needed some persuasion from a rubber mallet to seat. It should be a pretty snug fit.

One thing to watch out for with the Lite rails is even a slight mistake in tightening the lock up ring can translate into a pretty big offset at the end of the rail. I use either a
riser rail or ADM optics mounts to bridge between the rail and receiver. It is pretty important to get the tension on the lockup ring even. I like to remove the factory thread lock, degrease the parts and use blue loctite on the threads. This way I can more easily feel when the cap screws make first contact with the lock ring and I can gradually and evenly tighten them. I use a long bondhus allen wrench with a ball end to get things started and for the initial snug down. Then I tighten things up by 1/8 turns in a star pattern to keep tension even. You don't have to crush the lock ring to achieve sufficient tension, there can be a small gap between the rail flange and the lock ring but the gap should be even all the way around.

[LarryD]

Thanks for the tips Spam. I used a removeable carry handle to keep the rail lined up with the upper receiver but it still gave me problems. I like your bolt up method, especially about cleaning the screw threads prior to installing. The upper that I am using was new, but I don't know for sure where I got it. I am pretty sure that it is out of spec and the cause of all the problems. I built three rifles at the same time using parts from 3 or 4 vendors so I can't try to return it if I don't know for sure who it came from. The new upper from Bravo Co. (along with some other goodies) will be in next so I will give it another go. Thanks again.