Good news: cleaning a side charging upper is pretty much the same as cleaning a regular rear-charging upper, with just a few notes. From a high-level, here’s how to do it.
First, clear the weapon; remove the mag, open the action, and visually and physically inspect the chamber to ensure it is clear.
Remove the takedown pins to separate the upper and lower. If you can’t push the pins out with your finger, use a punch; preferably a nylon punch so you don’t damage your gun’s finish.
Some side chargers might have proprietary notes for disassembly; this one will focus on a Gibbz Arms upper with a Detent charging handle.
With the receivers separated, open the bolt carrier door and slide the bolt carrier out the rear.
Then, use an ⅛” Allen wrench to remove the front set screw from the charging handle, then take out the spring. Loosen the second set screw, remove, then loosen and remove the button head.
Then pull off the handle, remove the detent, and slide the transfer bar out of the slot.
Next, partially disassemble the bolt carrier group; remove the firing pin retainer, remove the firing pin, then rotate the enhanced cam pin and remove the bolt.
Now you can turn your attention to the chamber and barrel. It is very important to remember to clean from chamber to muzzle to avoid damaging the muzzle crowning.
Use a bronze bore brush appropriate for the bore diameter and use it to scrub some of the fouling loose from the bore.
If a bore light shows that the barrel is heavily fouled, use some bore solvent, such as Hoppe’s No. 9, to loosen the fouling before proceeding with the brush.
Once you’ve loosened the fouling, remove the bore brush, replace with a slotted cleaning jag and fit a fresh patch.
Run patches through the barrel, from chamber to muzzle, replacing each one until they come out clean.
Using a nylon brush and a little bit of fouling solvent, scrub off all the components of the bolt carrier group, then wipe them all clean with a clean, dry rag.
It is important here to make sure that the bolt carrier group is clear of fouling deposits and other debris, since side charging uppers don’t have an ejection port cover, which can allow particulate matter easier ingress into the action.
Once clean, set the components aside to dry fully before you reassemble.
Next you can turn your attention to the components of the charging handle. Using the same nylon brush and bore solvent, thoroughly clean all parts, then wipe clean with a clean, dry rag.
One area that could use a drop or two of oil is the transfer bar. Less is more; oil attracts fouling and grime and can gum up the action. Just a drop or two, then wipe off excess.
Clean the upper receiver itself, inside and out, looking for fouling deposits; scrub these loose with a nylon or brass brush, then wipe the upper dry.
Since this guide is only addressing cleaning the upper, it will not cover cleaning of the buffer tube system, fire control unit, or any other lower parts – though this will also be necessary periodically.
After all components are completely dry and have no fouling or solvent residue left on them, you can reassemble the rifle.
At this point, you can also reassemble your bolt carrier group in the reverse order described here, replace it in the upper, then reassemble and replace your charging handle assembly, and then re-attach the upper to the lower – your rifle is cleaned and ready to bring back to the range.
