Hello everyone! I hate to be that guy who has a question for his first post but I don't know where to turn.

So earlier this year I bought a complete Spike's Tactical upper receiver. I decided to go with the Troy Alpha rail since it uses the mil-spec barrel nut. My issue at first was the the rail was canted right no matter how I put the rail on. I diagnosed it to be the barrel nut not being on perfectly straight and sent the upper back to Spike's. Their amazing customer service supplied me with a new upper with the rail installed. The only issue this time is the rail was canted the other direction. Thinking the rail may have an imperfection I sent it to Troy and they supplied me with a replacement at no charge. The rail is still canted left unfortunately.

So my question is if I change rail systems with a proprietary nut will that nut also be off? I'm just kind of stumped on where to go from here. I would try it myself but I have a pinned and welded comp.
Thanks for any Advice!

**Oh and I know to some a crooked rail isn't a big deal but it is causing my iron's zero to be crazy and it really bothers me.

Have you tried contacting troy? I have the same rail system and it is straight as an arrow. Also make sure that the three prongs that lock down to the barrel nut are straight and in the correct position. If not this could cause some problems. Go around each screw and slightly tighten each one. Then come through and tight them real snug. Not to hard though. Let me know if that helps. If you have a mount. Tighten it between the upper receiver and rail for better alignment when clamping the rail down

Yeah I have tried every trick in the book. (Using a carry handle to straighten it etc..) Troy Even replaced the rail and it's still not straight. I believe the upper is causing it.

If that is the case the only other thing i can think of is the upper receiver is lapped wrong where the barrel nut seats. That is a spikes problem. Or just flat out the rail is wrong. Contact troy and see what they say.

Troy thinks it is the upper receiver as well. I guess I will call Spike's Tactical again.

What's causing it is the barrel nut is not indexed correctly.  I assume you do not have the tools to tighten or loosen a barrel nut or you would have fixed it yourself already, but IMO there is no part that is messed up, just the nut not indexed correctly.  Any smith that works on ARs will have what is needed to index the barrel nut correctly.  It is not rocket surgery and there is no need for the upper to be making cross country trips.
This is what needs to be done.
Remove forend.
Remove gas block and tube, and even this is not really needed for what little amount you need to move the barrel nut.
Clamp upper in upper receiver holder.
Use barrel nut nut wrench to very slightly move the barrel nut so it indexes correctly.  I have done this dozens of times on builds and you do not even need to remove the gas block or tube. All you are doing is every so slightly moving the barrel nut so when the forend locks down it lines up with the rail on the upper receiver and there is plenty of slop in the gas tube slop to allow this without removal.

Usually there is enough slop in the clamps that you can align it by just loosening the clamps, lining up, then re-tighten theclamps, but not always, not if you want the stop tab on the forend up against the upper receiver.

A shorter version of fixing this if you do not insist that the stop tab is against the forend (and just because it is against the forend does not mean your rail will be aligned).
If the forend is over rotated so that it needs to come back some to line up, back off the clamp screws and line it up.  Insert a card or feeler gauges between the stop tab and the upper receiver to help hold it in place.  Tighten up the three clamp screws.

If it needs to be rotated more, file a little off the stop tab.  This will void your warranty no doubt but you may never get it on right if the tab will not let the forend rotate enough.  File off the edge of the tab hitting the upper receiver until it lines up and then tighten the clamps.

Either way, this is a ten minute fix.