When you have a firearm like the AR-15, you need to do some regular maintenance if you want it to operate as it should. It’s best not to learn the hard way why it needs to be done. Assuming you’re starting with a clean firearm, the first – and arguably the most important – part of regular maintenance is to lubricate your AR-15.
How Much Is Enough?
While there are multiple schools of thought on the amount of lube, ranging from run it “wet as it gets” to “moving parts with advanced modern finishes can be run dry without hurting anything,” let me be the voice of reason here. For most operating situations, the AR-15 is best with a moderate coating of lubricant on anything that moves and has a metal-on-metal contact point.
While there are guys who might want to argue the point, I’m a believer that too much lube just turns into foul sludge and collects sand and miscellaneous grit that probably wouldn’t accumulate without excess lubricant to trap it and hold it on the metal surfaces.
“Wet” guys will talk about the sealed system. However, there are just too many opportunities for contamination with the way we actually operate these rifles in the real world for me to buy into that theory, never mind the condition of some of the weapons I’ve seen people dragging around.
What Kind of Lube Should I Use?
Once again, this is another slippery slope (pun intended) that gun guys can argue about forever. I have a couple of things to say on this subject, but for the most part, this is a “your mileage may vary” topic.
Some shooters prefer a multifunction solution that’s used to both clean and lubricate the weapon surfaces. These kinds of treatments tend to wear off or evaporate in the heat and stress of heavy fire situations fairly quickly, and you may need to touch up the job on your bolt carrier group before your day in the field is done. Other guys are turning to heavy greases that they feel “stick” better, providing better glide and a longer-lasting lube.
Let’s just approach this with a little logic: If you’re happy with the performance of your weapon and the frequency with which you need to lubricate the surfaces you’re treating, use what’s working. If you can hear the grind too often, you need to retreat when its inconvenient, or parts don’t seem to be moving smoothly, use a different product.
In most places, a multipurpose solution or a lightweight gun oil will do the job. When I find a place that needs a little more, like a freshly installed charging handle or those rails that the bolt carrier runs on, I’ll swab them with a touch of my favorite heavier-weight grease of the moment. Again, I don’t think more is better, because it can make a mess all on its own and collect foreign matter. It’s also worth remembering that a heavier grease can get stiff and sticky instead of slick and slow your system’s operation in really cold environments.
Doing the Work
Now that we’ve got the preamble out of the way, let’s get down to the real work of getting that lubricant in the right place to create the desired effect. Assuming you’ve just cleaned your rifle and it’s already stripped down, it’s empty, and the outer surfaces have been wiped down, we’ll begin with the lower receiver.
Many shooters will use different methods of oiling, from spray cans to needle oilers and swabs. I prefer to use oiled swabs in most areas rather than leaving behind drips and drops that may run through my system and collect in places where I don’t want them. If you want a drop somewhere, just dab an oil-wet swab against the area you’re after.
The Lower Receiver
When I begin with the lower, my first order of business is to give the fire control group a touch of light oil with a swab. I’m not about to douse the area with a spray can; the fine coat left behind by an oily swab is all you need to assure the free movement of these parts and to reduce any friction that might exist. Just touch the hammer sear contact to leave behind the fine coat you need. A drop of oil or a dab of a wet swab applied to the outside of your hammer spring and trigger spring coils will lubricate the pivot point on the pins that run through the lower receiver.
The Bolt Carrier Group
Some guys will oil the bolt carrier group as a unit. If I’m doing a full lube job after cleaning an AR, I’m going to go ahead and give the bolt surface a light coat of oil and wipe it down, removing excess if I’ve gotten a little sloppy. This cuts to the chase and makes it unnecessary to add drops of oil where it can run off and cause me trouble later. A finely oiled bolt reapplied to the carrier brings with it enough lube for the contact surfaces inside the carrier. You will want to swab the area that the cam pin rides against to keep the cam pin happy, and give the exhaust ports a small drop of oil or simply press/dab your oil-wet swab against those ports, giving your gas rings a little lube through the ports. Your bolt lugs should have a fine coat of lube from the bolt lube maneuver.
Once your bolt carrier group is reassembled, you need to apply lubricant to the contact rails on the upper and lower surfaces of the carrier body on both sides of the carrier. This is a place where some shooters will want a little heavier grease, but I’m a bit of a habitual “dry” lube fan. I’d rather do a regular touch-up to the bolt carrier group later than use a heavy grease and collect extra grime or gum things up in cold weather. If you’re really feeling obsessive about it, swab the inside of the upper where those rails contact to give yourself a little more comfort. It really doesn’t take a lot of lube to assure that your AR-15 runs smoothly.
The Charging Handle
The charging handle can take an all-over coat – it’s not going to cause you trouble unless you seriously overdo it and add a healthy helping of mud to boot. You just want to be sure you have enough lube in place to help it operate smoothly.
Switches, Buttons and Releases
Generally, I don’t find it necessary to give small controls like safety assemblies and magazine releases too much extra attention. If you’ve cleaned away any debris and given your surfaces a little multipurpose protectant, you’ve probably already given the control assemblies more lubricant than they need. If you install a new component or notice a little friction on inspection, just touch up the offender with your swab. Don’t leave extra residual oils to gum things up; you only want enough lube on any of these to take out any abrasiveness you feel on operation.
Lubricant Is Secondary to Fitment
If you don’t have parts compatibility problems and you’re running a fairly well-maintained weapon, you shouldn’t need much lubricant to keep your AR-15 in proper trim. If you find that you have a lot of problems with friction in a particular place and a light coat of lube isn’t handling it, you should probably be more concerned with how your parts fit together than the type of lube you’re using. Likewise, with the extremely tight tolerances that are required to produce today’s highly accurate rifles, it’s possible to create pressure or other problems with fitment with too much lubricant trapped in the wrong places. When in doubt, clean your components well and lube lightly.