I feel like I'm over thinking this, but my frustration is getting the better of me.

I can not get the alignment for the gas tube close to where it needs to be with several different tries and adjustments. This is a new DPMS pre assembled delta ring. What am I missing? Torqued several different times at different ft lbs and no luck.

Anyone with a suggestion? What simple thing am I over looking here? Greatly appreciate any insight you guys can provide.https://h33i.imgup.net/20170404_1c4e3.jpg
https://d32i.imgup.net/20170404_1c4df.jpg

My god. As soon as I post this I decided to turn my brain back on and pull it out of the vice and slide the ring from the back side.

This literally describes my day today

Better than me. I used a vice that was not bolted down today, had to stand on it on the floor. New aluminum rail and nut. My wrench has two pins to catch two wholes on the nut. Torqued it and got off center a little and started breaking chunks off the barrel nut... ... Think I ended up breaking off 3 sets of wholes. Eventually got it aligned, had to smooth out some rough edges to get it round enough for the locking ring and rail to screw on. Looks fine installed, looks like crap if you take it apart.... ... Should have used the wrench with a break bar from the start for better control...

Live and learn. My first build.

A couple things you can try:
-- torque to spec three times or more to season threads with aeroshell 33 grease on threads. The final torque value can be between 30-80 ft lbs. By seasoning the threads, via torqueing and loosening a couple times, the barrel nut position at final torque value will change ever so slightly to the right.
--try a new barrel nut so that the machining tolerances stack in your favor.
--lap or true the front of the receiver or use a different spare reciever. Barrel nut shims (brownells sells them) are helpful here and cheap too.

Don't exceed 80 ft lbs on the upper.

I use an alignment gauge type dowel to make it's up to spec once I get alignment close. A nifty trick is to increase the torque setting on the torque wrench 5 lbs, torque nut, check alignment, repeat, etc. when you get close

Also, some free float handguards don't require indexing -- makes this part a breeze. My favorite right now is Midwest Industries gen 3 mlok