Installed w/ Pics now - Trouble installing a Troy VTAC Alpha Rail

I'm baffled by this....

I had my barrel, barrel nut and gas tube installed already when the rail showed up. When I tried to install the rail, I would go on one of two ways: rotated way to far clockwise or way to far counter-clockwise once the female grooves grooves in the rail were aligned and slipped over the barrel nut.

I kept looking at the barrel nut and the gas tube and the alignment looked good. I figured maybe I was just looking at it wrong, so I removed the gas block and gas tube and adjusted the barrel nut until the rail on top on the Troy handguard aligned perfectly with the top rail of the upper.

I then slid the rail off and looked at the barrel nut alignment with the hole in the upper receiver the gas tube passes through. One of the "teeth" on the barrel nut is pointing straight up at 12:00 blocking the path of inserting the gas tube into the upper. It seem to be exactly 1/2 tooth rotation off which is off as far as it can get.

Separate issue, the anti-rotation tab on the handguard is in the way (hitting the upper) when the rail is aligned correctly. When I tray to slide the rail on, the tab hits the upper. I had to turn the rail around backwards (no tab on that end) to get it to slide all the way on.

The upper is a Mega billet one, and I suspect that may be the issue here since the profile isnt exactly the same as a typical forged one.

I am waiting for my alpha rail to show up in the mail. In the mean time I researched how to do the install.

The rail is supposed to go on tilted to the right if you are looking down the muzzle. Then rotated counter clockwise after it is seated against the upper to align the top rail. Then tighten the tabs equally.

Looking down the muzzle you need to turn your rail to the side a bit and slide it down over the barrel, line the tooth up on the rail to the right side of your receiver and then twist/wiggle it in over the barrel nut while turning counter clock wise. You'll need to use a little bit of force but it shouldn't be excessive. If you get the rail over the barrel nut but can't get it lined up correctly with your receiver then you aligned the rails tooth wrong; do not force it! Back up and fix your alignment.

Remember, if you're looking down the muzzle then you'll be aligning the rails tooth on the right side of your receiver then you wiggle/slide it into the center position.

Hope this makes sense. Take a look at the receiver end of the rail, on the inside, and you'll see the grooves - this helped me understand how to align it correctly.

With the barrel nut and gas tube properly installed, slip it on with the tab to the left of the upper receiver and with it pushed on far enough to align the groove inside the tube with the points on the barrel nut then rotate the handguard to align the rail and lock down the 3 allen screws.

EDIT: djmorris beat me to it.

EDIT, EDIT: just checked the paper instructions I have from a recent purchase and also online, and Troy nor Viking Tactical show rotating the tube in the instructions.
However several threads in the forum have gone over it.

Thanks guys!!! That did it. :thank_you2:

The instructions are worthless. The word rotate is not even in there! :angry:

http://i303.photobucket.com/albums/n...ing/img002.jpg

I have two of these rails both 13" and I was having the same problem as you earlier today so I backed up and read the directions (don't tell my wife that I know how to read directions) I loosened up the three screws and by accident more than anything I slid it on off centered and then rotated it into place with no force needed at all. It is just a matter of tightening down the screws a little at a time to keep alignment.

Hope this helps.
Dave

If you've a riser or other mountable item that can be put on as a bridge over the handguard to receiver gap it helps keep very good alignment while tightening the screws.

It's on. It looks and feels great. Fits-up solid and tight.

FWIW, the MWI .936" lo-pro gas block does not clear the ID on the handguard. It's on there and it barely touching... on the bottom only, but it IS definitely touching.

I had to remove the handguard lower set screw/assembly/tab/thing completely, slide the HG over the gas block, sneak the tab back in there, then finish the install.

I finally found a Troy .936" low-pro block online. They seem to be out of stock damn near everywhere. They look lower profile on the bottom from the pics I've seen online. Hopefully it will clear. If not, I'm just going to grind the bottom of the MWI one once it is installed.

Hear are some pics. 24" Barrel, w/15" Troy VTAC Alpha

http://i303.photobucket.com/albums/n...s/IMG_1391.jpg

http://i303.photobucket.com/albums/n...s/IMG_1389.jpg

http://i303.photobucket.com/albums/n...s/IMG_1386.jpg

http://i303.photobucket.com/albums/n...kworks/6jb.jpg

May I ask what purpose the musket barrel serves and why you selected it?