There's no voodoo here - when lubricating an AR or any gun, this is your universal rule: Learn to examine your guns in terms of "friction surfaces" - when this becomes habit, guns reveal nearly all of their operational and reliability secrets, and it tells you exactly where to lube, even on guns new to you.
A key thing to internalize as part of this, is that friction is cumulative in a gun - it adds up, and every gun has its friction tipping point, where any friction beyond that will cause a malfunction. Even the tiniest spots of friction need lubrication, if you want maximum reliability. Direct-Impingment ARs are particularly sensitive to this, but also gain exceptional reliability with proper lubrication. In no small part, this sensitivity is related to the 1000F gas blasted into the action, and the super-heated fouling particulate it carries, which continues to cook off lube far longer than the gas itself.
Before we address the specifics of where to lube, let's first discuss how much to lube.
How Much to Lube?
In short, the wetter the better. With any lube, not just ours. There are too many lube myths to unpack in one post alone, but lube heavy if you want maximum reliability - every bit of sand or fouling in your friction surfaces is sucking energy out of your moving parts and slowing them down, and lubrication is the only thing that mitigates this.
We'll address these myths in other posts, but as long as you don't get oil into the mag or trigger (or more specifically, irrigate sand and fouling into those places), it's just about impossible to "overlube" a gun. And as long as mags and ammo are good, literally about 98% of all malfunctions are friction related, in one way or another - "FTEs" and FTFs are symptoms of too much friction in almost all cases, not the actual problem.
It is extremely difficult to "over lube" with our grease for another reason: the gun will push out all it doesn't need when you reassemble - just wipe it off and put it back in the bottle (it's still perfectly good), dry-cycle a dozen times and wipe off any further excess, and you're good to go.
The "excess" remaining in the empty spaces inside the gun will stay put, and significantly enhance the sealant effect of the grease, keeping your parts moving fast, smooth, and reliably.
Bottom line: if the gun doesn't push out a bunch of grease when you reassemble, you didn't put enough on. If it does not feel like "snot-on-glass" when you cycle, you missed a spot.
This heavy application if for maximum reliability - a thin coat still works very well for a common range day of just a few hundred rounds, and will be far more reliable than gun oils can be, so you can economize. But if you need to rely on your firearm, grease it heavily.
LUBRICATING AN AR - WHERE SPECIFICALLY
Cam Channel and Cam Pin: Slather the entire channel and the upper half of the cam pin. Slather - especially when running suppressed. This is an area of tremendous - and unrecognized - friction and mechanical disadvantage when the cam goes to cam-over at the cam-shoulders. It also has 700F-1500F gasses pumped into it, full of friction contaminant, almost directly from the gas tube as the BCG pulls back - this cooks off and/or blasts away gun oils, while packing it with super-heated friction contaminant - creating a tacky abrasive right on those cam shoulders and the cam pin.
When bolts break at the cam-pin hole, it's because of this - the tremendous torque that's being applied to it, because of the friction on the cam shoulders. So, lube heavy, and slather the grease in the channel.
Bolt Carrier: Fully coat the 4 rails and sides of the gas key if rub wear is present. For max reliability, lube heavy - with oils, the wetter the better, up to the point where the lube may get into the mag, which you do not want. With our grease, a thick coating on these bearing surfaces.
Upper: Coat the 4 opposite mating surfaces on the upper where BCG rides - yes, lube both mating surfaces (carrier's and upper's), including the entire length of the upper, to ensure sufficient lube and no dry contact surface, and to help with the sealant effect.
Gas rings and bolt tail: Leave dry, do not lube - the gas is direct, under pressure, and far too hot for any lube to endure long enough to matter, and the friction surfaces are not large enough to be significant in the total amount of friction surface in the gun to matter, if everything else is properly lubed.
Extractor: Nothing on the claw face that may contact the casing. Lubing the pivot pin is debatable, but would require disassembly to apply our grease.
Locking Lugs: There are few situations where lubing AR locking lugs will enhance reliability to be worthwhile, over the risks that come from lubing them, so leave dry. The primary risk comes from lubes heated beyond the point where they begin to break-down and polymerize, and then start cooling - it can create a tacky substance. And for fresh guns that need first-round reliability, the rest of the gun will have so little friction from being properly lubed that it does not provide enough added benefit. Readers are welcome to contact us directly if they'd like details on when it may be worthwhile.
Firing Pin: Never lube, on any gun, without exceptional and clear need to do so (ie, rust), for three reasons:
There simply is not enough friction between firing pin and channel, compared to the energies applied by the hammer, to require lube at all
The energies applied by the hammer will displace or crush sand or dirt that may get in to the firing pin channel if dry, but a wet pin may retain enough sand to be too much to displace or crush,
Firing pins are usually the first place a gun will shut down in cold weather. One drop of oil is enough to create contact between pin and channel almost the entire length of the pin - and when cold enough, any lube will go from reducing friction, to acting like an adhesive. This channel is also extremely challenging to clean lubricant out of fully, down to bare metal, making it subject to freezing even if the shooter thought they'd cleaned it out well. Combined, always run firing pins dry, unless presented with a very serious and clear need to lube it, such as rust.
Magazines: Never, ever oil or grease, for 4 reasons:
In complete opposite of the action, mags run best dry, and worst wet, and have a very narrow window of reliability between energy and friction - the energies of the springs compared to the resistance of the ammo and follower are narrow, because if too powerful the action would have a hard time stripping each round during cycling, and too light the springs wouldn't move the ammo fast enough. Being of looser tolerances, if dry, sand will tend to want to drop below the follower during cycling. But if wet, it may stay in place and accumulate, adding enough friction to overcome the narrow window of reliability.
Different geometries and energies mean different friction experiences - the fast speed of an action, combined with tight, long geometries, can allow a single piece of sand in an action to cause binding, while slower mag followers with shorter and looser friction-surface geometries may not experience such binding, and can handle a little dry sand. But by adding just a little lube, that sand can add up enough friction to keep the ammo from moving fast enough up the mag.
Lube on ammo will virtually guarantee sand sticks to it, and cause a malfunction in the chamber during chambering if sufficient enough.
Lube on ammo can dramatically increase the pressure on locking lugs. When ignited, the gasses treat the bullet and casing equally, trying to turn each into a projectile out either end of the barrel. Casing brass, however, being soft, first expands against the chamber walls during firing, serving to seal off the chamber from expanding gasses, and also creates a significant amount of friction against the chamber wall that would otherwise be directed into the locking lugs of the bolt. Lubing a casing plummets that friction, and can increase pressures on the bolt lugs by up to 40%, depending on cartridge design.
Trigger Group: Similar to the firing pin, don't lube unless there is clear and compelling reliability need to do so. Dry sand will get crushed by the power of hammer/spring parts, or it will fall out entirely. Wet sand, however, can accumulate enough to cause a physical blockage preventing sear engagement.
Bore, Chamber, and Ramps: Never lubricate, except for storage or rust prevention, and even then only use oil. For identical reasons mentioned in the last point on why not to lube mags, any lube in the chamber can dramatically increase pressure on locking lugs, with lube on ramps possibly also allowing sand to be stuck and carried into the chamber. Fluids in a bore will be pushed out by a supersonic, high-pressure squeegee - if there's enough liquid, it will accumulate in front of the bullet and possibly result in a splitting or detonation of the barrel. Oils have been very forgiving to shooters on this, in no small part because oils, especially thin coats, tend to dry out quickly. But our grease does not - it is also much thicker than oils, and is technically both a solid and a liquid. It also has components that, while microscopic, are solids (the boundary lubricants). While our grease is a phenomenal rust preventative, it's unlikely it would be easy to get every bit of it out with one or two dry patches, and could be dangerous if present in a bore when fired. The narrower the bore and the higher the bullet velocity, the more the danger.
General: Lube any other shiny spots were you see rub wear, or know parts are sliding against each other. Look for any and all friction surfaces, especially hidden ones, and lube them. Even the tiniest spots of rub wear need lube if you want maximum reliability
In summary, with all guns: learn to think in terms of friction surface, and lube heavily. Friction is cumulative, so do whatever you can to keep it from adding up.
Be sure to hit us up in the comments section with any questions.