Troy Alpha help needed

Bought a used Troy Alpha from a member here, rail looks really good. This is the rail with the three screws to attach to the barrel nut and not the rail with the pinch piece at the bottom. I have an incomplete upper receiver and 2 barrel nuts and my issue is I can't get the rail hardware to clamp down on the barrel nut, I can't figure it out.

The rail hardware appears to be in great shape, I believe it's in place correctly. The gripping finger (for lack of knowing the correct term) is oriented correctly with the tail in the groove of the rail and the beveled end just barely making contact with the edge of the barrel nut. Anyway, I crank down on the hardware with the barrel nut in place and I can't get the hardware fingers to grip the barrel nut tightly. Tried with two different barrel nuts. I torque the screws down and can pull the rail right off the barrel nut with no effort. Yes, the hardware is very loose when I slip the barrel nut in the tube, it should be going in all the way. There's no crud inside the rail and the screws tighten down to the rail.

One barrel nut is probably a Palmetto and the other is unknown but in excellent shape. Youtube makes this look easy but I'm struggling. Now the only difference between what I have and the videos is I don't have a barrel yet. I just wanted to put the rail on temporarily to get a feel for it, but not having a barrel shouldn't make a difference as far as I can tell.

Anyone have any pointers? All I can come up with is get yet another barrel nut.

You need a barrel. The three locking tabs are not "locking" into the barrel nut.

Let me know if you can't figure it out. I know 100% that rail works, if it's defective I will refund your money

This might be a crazy guess on my part, but I'm guessing you don't have an actual barrel installed?

edit. Oops. Missed the part about not having a barrel. That's the problem. Your barrel nut is run too far down since you don't have a barrel. Back the nut off about 1/8" like it would be with a barrel and you should be good to go.

Kwando, thanks for the reply. I can't visualize why this doesn't work without a barrel. I"ll sleep on it, and think more on it tomorrow but thanks for responding, I appreciate it.

Ray, I do NOT have an actual barrel installed yet. You are correct.

See my post above. I had to edit once I realized you had no barrel.

Okay I get that about the barrel nut being flush with the receiver. However I also just pushed the barrel nut into the rail, no receiver attached, pushed the nut in as far as I could and still couldn't get the hardware to grip.

You'd have to push the nut into the handguard and rotate the nut so that the teeth on the nut turn into the slots inside the handguard.

You might have to trust me on this. I had a Bravo rail (same as Alpha but a quad rail) and tried to mock it up without a barrel with no success. Installed the barrel and... Presto. Went right on as designed and locked up solid.

Okay. I didn't do the rotating part. Just pushed the barrel nut in and tried to tighten the hardware. That has to be my issue.
Thanks Kwando & Ray, I appreciate the speedy responses.

Basically, once you twist the barrel nut into the slots inside the handguards, those little tab things on the handguard pull the handguard forward tight against the back of the teeth on the nut.

Not it sure I am explaining it clearly. Lol.