Fortis night rail question...

[KW900A]

I finally got around to finishing my upper a few weeks ago and just noticed that the top rails on the upper and rail are off, by literally a hair. But enough to annoy me that I didn’t catch it when I was assembling it.

Question is, with that two piece nut, how much does it need to be loosened to turn the barrel nut just a shade? I know the inner nut locks the rail to the barrel nut, but I’m afraid to heave on the barrel nut with the inner one ran in, unless that can be confirmed to be ok. I hate having to back it off, but I don’t think it’s avoidable.

[UWone77]

Let's see a pic of how off it is.

[KW900A]

Quick iPhone shot with flash to show off the dust.

It’s easier to feel than see, but using the flash brought it out better

[KW900A]

Do you think that’s an issue? It isn’t much, it’s close enough that when I assembled it, I thought I was feeiling the natural gap between the receiver and the rail.

[Former11B]

Does it do that just sliding it on or when you snug it up?

I always take a removeable carry handle and put it half on the upper and half on the rail to keep things aligned while I tighten the screws down. Has worked on every rail I own except one Aero Quantum that has no 12 o’clock picatinny

[UWone77]

Is the other side slight off too?

For what it's worth my Night Rail has a slight gap between the handguard on upper as well.

[KW900A]

It’s clocked slightly off, so the overhang in the pic equals an ‘underhang’ On the other side. I don’t plan to run open sights on this one, so it may not be an issue.

To answer your question F11B, if I recall correctly, the positioning of the rail is determined by the clocking of the barrel nut. The one thing I hated about assembling this was, once the nut was torqued, I had to horse on it pretty damn hard to line the groove up for the gas tube. Once I got it to that point I didn’t turn it anymore, but it looks like if I want that rail to be perfect I’m going to have to. It almost seems like a shim would make that step easier, but I didn’t design it.

[UWone77]

It would annoy me to. I think you’re going to have to back it off.

[KW900A]

I expect that’s the case. Shouldn’t take me long, just hate having to do that. Thanks for taking a look.