Install free float

To make sure the lock ring faces the receiver, have it installed atop the barrel. Finally, hand tight the barrel nut. Also, make sure to avoid using the torque wrench for loosening. After which, you need to re-torque to 30ft.

Put the torque wrench away and loosen again. For the last time, torque it to 30ft and inspect the line up between the barrel nut and gas tube hole situated in the upper receiver. In total, you need to do the torque sequences three times to enable the threads of the upper receiver and barrel nut for efficiency.

When doing this, make sure the wrench does not exceed 60 ft. The holes should be aligned at 35 foot-pounds. Meanwhile, the gas tube needs to be centered in the nut hole without the edges touching.

You can use the bolt carrier to inspect for proper gas tube installation. All you need to do is to insert the bolt carrier group to the upper receiver. You need to put the blue threadlocker onto the set screws of the gas block. After which, glide the gas block assembly onto the barrel nut to efficiently upgrade your rifle. Finally, reinforce the set screws on the block properly once you make sure the gas port is aligned before moving to the top rail alignment.

As for the last step, reinstall the muzzle device with the crush washer and line it properly. The flash hider comes together with the vented ports facing upward and the muzzle brakes generally together with the ports facing the sides.

You need to put a blue threadlocker up on the anti-rotation screw situated at the handguard base. Make sure to hand tighten it. Reassemble your upper and lower receivers after reinstalling the charging handle and the rail bolt carrier group. You can place iron sights on a quad rail to assist your aim. However, these sights are typically swapped by telescopic sights for precision applications.

Tap out the gas tube roll pin with a 2 roll pin punch and inspect the front sight gas block. If it has tapered pins, drive them out with a cup tip punch from the small side. If unsure, measure the pin diameter on each side first.

If the pins are difficult to remove, apply penetrating oil, let sit overnight and try again. Sometimes applying light heat to the area also helps with removal.

If the gas block is a clamp-on type, use a hex key to loosen the set screws. Remove the original front sight gas block assembly from the barrel. If it sticks, gently tap on it with a soft-faced hammer until it slides off the barrel.

Remove the handguard retainer and gas tube. On a bench block, align the gas tube through-hole with the large hole facing down into the new gas block and use a roll pin holder to start the roll pin. Drive the roll pin flush with the gas block.

Remove the anti-rotation screw from the bottom of the new handguards and unscrew the new barrel nut, removing it from the handguards. The first thing we are going to do is ensure the gun is unloaded. Clear the weapon and remove any live ammo or magazines.

Now separate the upper and lower receivers. The same goes for the BCG and the charging handle. Once the handguards are removed you can set them aside.

Attach your upper vise block to your upper receiver, and then to your vise. We need to remove your muzzle device. Regardless of how, go ahead and remove the muzzle device. Now we have to remove your gas block. There are two types, gas blocks with front sight bases and low profile gas blocks.

With an FSB gas block, we need to remove the gas tube. If you did not have a front sight base, you get to skip this step and you can just remove your gas block with the tube attached. Once the old barrel nut is removed you can then clean the threads and ensure they are ready for the next barrel nut.

Apply chrome moly grease onto the threads of the barrel nut. You can then hand tighten the barrel nut down. Set the torque to foot pounds and attach the crowfoot wrench to the torque wrench.

Torque the barrel nut down appropriately. Now we are going to use a breaker bar with the crowfoot wrench to loosen it once more. Breaker bars are a safer tool to use. We are going to loosen and retighten the nut three times to season the threads. This is in the old Colt manual and ensures the barrel nut is going nowhere. On the final tightening, you can go over 30 ft pounds. Max 60 ft.