FF Tube Removal / Installation

MikeyT

MikeyT

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Hello,

I'm looking for some help in removing a Dlask free float quad rail handguard. I've got the flash hider and front sight off the barrel, but I cant figure out how to remove the actual rail system - it's killing me :( .

Any advice would be greatly appreciated. My new Larue rail arrives next week and I'd like to be prepared. ;)

Thanks -
 
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FF handguard removal

If it is a two piece handguard the long section is screwed into the barrel nut just in front of the upper receiver. A strap wrench should take it off with no problem.
 
I had one on with locktite on the threads. I needed heat and the leather wrapped jaws of a pipe wrench to 'help' it off.
 
MikeyT said:
How do I tell? The handguard seems to be all one piece, and seems to cover the barrel nut entirely.
Click to expand...

Lets see a pic of it, most of those use a different barrel nut its threaded on the outside for the tube, like Willy said the tube should just unscrew off.
 
Thanks guys, you were right. The combination of strap-wrench and heat-gun got it off. The threaded barrel nut was absolutely coated in lock-tight. What a piece of junk.

The Larue rail comes with a new barrel nut - is there a specific amount of torque I should apply when tightening it?
 
FF tube

As I recall, about 35 ft/lbs should do the trick. You may have to go a little higher as you line up the gas tube holes but something in that range (more than less is better) will put you in good shape.
 
willwagspal said:
As I recall, about 35 ft/lbs should do the trick. You may have to go a little higher as you line up the gas tube holes but something in that range (more than less is better) will put you in good shape.
Click to expand...


Is there a particular way to line up the gas tube holes properly, or do you just eyeball it? I'd feel pretty silly if I got it all back together and my front sight was tilted to one side.
 
FF tube installation

There is actually a guage that Brownells sells to check straightness. It is really just a rod the same diameter as the gas tube. You insert it through the hole in the nut or delta ring into the upper. I have found that a drill bit (shank end - not the cutting part) that is the largest that will still go in the hole gives the same result. Insert it through the barrel nut hole and upper gas tube hole. When the bit runs parallel with the bore the nut is properly lined up. If it isn't you will have to tighten/loosen the barrel nut till it is. Seems to work very well.
 
Never mind - I misunderstood. I was referring to the gas port in the barrel - making sure it is pointing straight up. I assume that when I get the barrel off it has some notch or indexing method and doesn't spin when tightening the nut.

I will use the gas tube itself to check that the holes in the nut line up with the gas tube hole in the reciever.
 
MikeyT said:
Never mind - I misunderstood. I was referring to the gas port in the barrel - making sure it is pointing straight up. I assume that when I get the barrel off it has some notch or indexing method and doesn't spin when tightening the nut.

I will use the gas tube itself to check that the holes in the nut line up with the gas tube hole in the reciever.
Click to expand...


If it`s one of those clamp on style gas blocks, I dont know of any good way to make sure its directly over the gas port in the barrel, I guess just level the top of the rail.

I used one of those YHM 2 piece gas blocks, I used a piece of a drill bit same diameter of the barrel gas port hole to line them up perfectly.
 
MikeyT said:
Never mind - I misunderstood. I was referring to the gas port in the barrel - making sure it is pointing straight up. I assume that when I get the barrel off it has some notch or indexing method and doesn't spin when tightening the nut.

I will use the gas tube itself to check that the holes in the nut line up with the gas tube hole in the reciever.
Click to expand...

The barrel should have an index pin at the breech end that fits into the front of the receiver. When properly mated, this aligns the barrel and prevents it from twisting when you screw the FF tube on. All you have to worry about is that the the gas tube hole in the receiver lines up with the FF tube hole as mentioned before. Go here for complete step-by-step instruction on how to assemble your AR15 :D

http://www.ar15.com/forums/topic.html?b=3&f=4&t=226782
 
That's great. I've got the barrel nut off and I see the index pin. The new RIS should arrive in a couple days and it looks like the only slightly tricky part will be ensuring that the front sight/gas block is aligned on the barrel properly. Any hints on front sight installation?
 
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