This is how it looked before with the smooth sided upper.
Got my tools in hand and ready to tear down and build. Tools needed are:
Socket Set (for optics)
Fat Wrench (inch pound torque screwdriver)
Punch Set
Hammer
Allen Keys
AR Armorer's Wrench
AR Vice block set
Torque Ratchet (foot pound)
Large flathead screwdriver
Picatinny riser (to align upper with railed forend)
First up was to remove the Magpul MOE forend, drift out the two pins that hold the front sight and the single pin that holds the gas tube. Just need to back them out far enough to remove the barrel nut. Normally I would remove the flash hider, too. However, there was enough room to just back out everything down the barrel without removing the flash hider.
When putting an upper receiver into the AR vice block, it's a good idea to insert the bolt tool. It acts as a spacer inside the upper, so you don't accidentally crush the upper by clamping down too hard with the vice.
There are generally two types of barrel nuts. SPROCKET style for traditional hand guards and PIN style for free float. The Armorer's Tool is usually set up to do both. I highly suggest you use the correct side of the tool. Some Armorer's Tool only has the PIN configuration. That's OK. The PIN tool will work on the Sprocket barrel nut, too. It's just that the sprocket style has less meat for the pins to grab onto, and I have seen some barrel nuts bend because of that.
With the barrel removed, I replace the smooth upper with a traditional upper that has a forward assist and ejection port cover. The DPMS Smooth side upper will be used on my 20" Varminter later.
Once the barrel was reinstalled and the barrel nut torqued to 30ft-lb, I aligned the barrel nut, spring, snap ring and Delta ring, so the gas tube can go back into the receiver. This is always the tricky part. You have 4 things to line up so the tube goes into the receiver straight. If the barrel nut is not lining up, torque it some more. The barrel nut should be between 30-70ft-LB.
Once that all checked out, I reinstalled the front sight by reinstalling the two pins. Inserted the gas tube and installed the roll pin that retains the tube into the front sight block.
To check that the front sight block is aligned to the gas port on the barrel, I plugged the chamber with a dummy bullet, inserted my blow gun into the muzzle and fired air into the barrel. The air should travel up the front sight gas block, through the gas tube, and into the upper receiver.
If it all checks out, then reinstall the Magpul MOE forend.
Done! Now this AR is as light as possible!
Installed a Magpul MBUS on the rear and an Aimpoint Knockoff on the front. Torqued the scope base to 20 in-LB.
Moving on to project #2