Hi STRADALE and welcome to the forum!
Here is a copy of Kip's (Carriercomp) instructions:
Tools required;
> Heat gun.(Refrain from using flame devices, torches, etc., they are overkill and have the potential of discoloring the finish on the receiver)
> Snap ring pliers.
>Stiff nylon or brass bristled tooth-brush, Q-tips and acetone.
> Rubber grip pad. (Similar to a jar lid gripper, or even a piece of tire inner tube)
>Padded vise. (not required but helpful if done alone without an assistant)
Before proceeding please ensure the firearm is completely unloaded, clear mag tube and chamber, firearm on safe.
Lock the bolt to the rear, then remove the factory barrel nut (by hand), set the barrel, bolt group, and handguards to the side. Using snap ring pliers set to compress when gripped, carefully remove the spring retainer from the end of the factory mag tube, (keep it aimed away from your face, with your other hand over the end so that the spring can be safely contained when it is "set free"). Then tilt the gun downwards, allowing the spring and follower to fall out. Place gun in a lightly clamped padded vise (ensuring the bolt release button is not clamped), between your knees, or in the hands of a competent assistant. Using the heat gun set to a maximum 400 F, apply direct heat to the full circumference of the mag tube where it meets the receiver, allowing heat to reach the receiver as well, continue rotating the heat around the junction until the two are beyond unbearable to touch (using an infra-red thermometer if available, you will typically see results when the receiver temp nears 250F), favor application of heat to the receiver, as it retains heat more efficiently. At that temp (around 250F) you should be able to begin twisting the factory tube off [ccw](here's where the rubber grip pad does double duty as a heat shield, and provides much better grip than bare hands). Do not use a pipe wrench for a few reasons, 1st it will damage your factory tube, but foremost it will provide excessive torque that may allow you to force removal before the loc-tite is ready to let go. Once it starts to turn, the battle is won, just keep it turning until it is free. Next clean the internal threads with acetone, Q-tips, and the nylon or brass tooth brush. It will look scary at 1st since the residue from the factory loc-tite is chalky white, but once you have it all cleaned off, you should be looking at the pristine black anodized receiver threads where the old tube use to be. You are now ready to install your replacement tube. Don't forget to transfer the handguard's stamped steel rear brace onto the new tube BEFORE threading it into the receiver, it is a "captured part" that has to be in place during assembly. Most people opt to fore-go the use of loc-tite, simply torqing in their new tube as tight as can be done by hand. If you use loc-tite, make sure you check the data sheet, and select a grade that can be heated for removal with LOW HEAT like the factory used. Typically just a drop of medium strength Loc-Tite brand "blue" will be sufficient if you use any at all. Replace all the remaining components, and enjoy!!
Later,
Hookster
