AR 15 Free Float Tubes – How to Install Video

AR 15 Free Float Tubes – How to Install Video

Midway USA
Midway USA

Columbia, MO – -(
This video and web page will show you just how easy it is to install an AR15 free float tube on your AR15 upper.

This whole job, from beginning to end, takes 30 minutes to 1.5 hours, depending on your skill level.  If you can tighten a few nuts, then you can install your own AR15 free float tube to customize your black rifle just the way you like it.

This section will cover installing a YHM brand ultralight carbine float tube ($144.95)

AR 15 Free Float Tube
AR 15 Free Float Tube

Ok, lets cover the necessary tools. What you need:

Since this procedure requires removal of the AR15 barrel and barrel nut, you will need many of the same tools as you would when building a complete AR-15 upper.

Gunsmith Tools you will need:

In addition, depending on the AR15 free float tube you choose, you might need a special float tube wrench. I opted to get this from YHM, didn’t need it, but since this was my first one, couldn’t hurt.

You will also need a couple punches. You just need a good sized (1/4″) soft brass punch and a steel 1/8″ punch. I got this punch set and really like it…. but you can find what you need at sears or harbor freight, etc…

That’s it for tools!

Now here are the step-by-step instructions:

1. Remove the upper from the rifle. Remove the handguards. Using the instructions listed in the above posts, remove the barrel from the upper receiver. (you don’t have to fully remove the barrel…. just the barrel nut/delta ring assembly, and you could leave the gas tube in the FSB) We will be assuming a full dis-assembly for this guide) You MUST remove any type of muzzle device first…. flash hider, muzzle brake, etc… If these are permanently mounted, then they will have to be removed. Depending on their method of attachment, it may be advisable to have a competent gunsmith remove them and reinstall them.

Now we need to remove the FSB (front sight base) from the barrel. The pins in the FSB are typically tapered. This means they can only be removed one way. (I am told that RRA and LMT use straight pins, not tapered, so those should be even easier) Look on both sides of the FSB and determine which side of the pins is the SMALLER end. It should be the left side, and we will be knocking the pins out from left to right. NOTE – Stag Arms has been shipping uppers with FSB taper pins on the opposite side of most uppers – so be sure to examine your FSB!

2. Support the barrel so that when we knock the pins out, we wont stress the barrel at all… I used a couple pieces of 2×4. Using a large diameter (~1/4″) brass punch, firmly knock the pins loose. Use masking tape all round the FSB is you are worried you might slip and scratch something. I must admit… on most of the barrels I have done, a couple sharp hits with a punch knocked the pins loose…. but I finally had one Bushmaster 20″ barrel that the pins absolutely would not come loose on. I ended up having to dremel the FSB down and then was able to punch them out, but I ruined the FSB. I was replacing with a flip up FSB anyway, so it wasn’t a great concern… but keep this in mind, should you come across one that is not very friendly.
It will take the most force just to break the pins loose… once they are loose, we can use the small punch to tap them all the way out:

3. Now, lubricate the FSB and the area on the barrel in front of the FSB with CLP, WD40, gun oil…etc… this it to ensure we will scratch the barrel as little as possible upon removing the FSB. Wiggle the FSB back and forth to loosen it… you may need to put the barrel back in the upper receiver to hold it for this step. Then, pull the FSB from the barrel, going slow and taking care. If you go slowly, you shouldn’t place any marks on the barrel from this step. Remove the barrel nut and delta ring as well:

4. Disassemble the YHM free float… into the float tube, aluminum barrel nut, and float tube lock nut.

5. Insert the barrel into the upper receiver. Apply a little moly grease to the threads of the upper receiver.

6. Install the barrel nut, and get it snug (this should be tightened just like any other barrel nut, torque it to spec)…. then tighten until you align with the next possible gas tube hole. Slip the gas tube in from the rear to ensure you are aligned:

7. Install the float tube lock nut. Thread it all the way to the rear, flush with the back edge of the barrel nut. I like to use a little blue Locktite on this, to ensure it wont back off in the field. A little Loctite makes all the difference!

8. Spin on the float tube…. right up to the lock nut. Ensure the rail is aligned with the rail on the upper receiver. I used a A3 carry handle, half on the receiver, and half on the float rail, to achieve this. Then tighten the locking nut. You can use the YHM tool for this, or a hammer/punch/flat blade screwdriver.

9. Now install the FSB back on the barrel, and the gas tube. Remember to put the roll pin back in the gas tube if you removed it:

10. Using the large brass punch, tap the taper pins back in, from the RIGHT, to the LEFT, this time… driving them home.

11. DONE! Wasn’t that simple? Finished product… time to go shooting!

There are several different types of free float tubes on the market, and their installation will vary slightly from this specific one… some have integrated barrel nuts, some require a strap wrench, but all have the same principles involved above.  Source:

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Charles Parslow

When installing the base of the tube, what is being applied to the thread? Is this material also applied when re-installing the flash hider?

Thanks Much,

Charles Parslow