If you’ve taken an AR 15 build kit and turned it into a rifle, then you’re likely pretty familiar with its insides by now. This is one of the reasons we encourage you to build an AR 15 rather than simply buying one: You’ll truly learn the weapon’s assembly, and you’ll need to know this stuff because your AR 15 will need to be cleaned eventually.
For this article, we’re going to talk about level 2 maintenance for an AR 15. This goes a bit beyond simply cleaning your rifle’s main parts, like the barrel and lower. This level of maintenance is necessary once the rifle’s been through several thousand rounds, or when it’s just not functioning right.
Nomenclature of the AR 15 Kit
If you’re reading this on our website, then we assume you’ve built your rifle and you therefore know which part is which. We can spend an entire article just identifying AR 15 parts, so if you haven’t built an AR 15 or are just not familiar with the platform yet, some of this may not make sense.
You won’t be able to see your gas rings until you remove your bolt from your bolt carrier group. Opposite from the bolt face near the very end of the bolt are three small rings, stacked on top of each other. These rings will occasionally need to be replaced, especially if the rifle doesn’t cycle.
There is a simple test for this. With the BCG assembled and removed from the gun, fully extend the bolt from the BCG. Now set the entire thing face down on the bolt on a flat surface. If the bolt collapses into the BCG, it’s time to replace the rings.
Replacing the rings is simple, and they can be found just about anywhere that sells gun parts. Most gun stores will carry them. It’s simple, and takes all but three minutes to do.
Since we are talking about the bolt, let’s talk about the extractor spring. You can access it by removing the extractor and it’s retaining pin. This small brass spring and plastic post are often the root causes of a lot of different malfunctions. It’s hard to tell exactly when these springs go bad, but if you start having ejection issues it’s wise to replace it before you take further action. They are also affordable and very easy to find.
If you are really pounding the pavement with your rifle you may start getting random cycling issues, mainly the bolt not going fully into battery. If you get this issue it may be a worn buffer spring. (That comically big spring found in your AR 15 lower parts kit) A weak or ‘collapsed’ buffer spring is typically caused by thousands of rounds of shooting. Springs weaken through compression and release, so it is possible to wear out a buffer spring after quite a few range trips.
To see if your buffer spring is weak you need to measure it. A carbine buffer spring should be replaced when it’s shorter than 10-1/8th inches, and a rifle buffer spring should be replaced when it measures 11-3/4s inches or less.
Our Carbine Stock & Buffer Kit includes all-new components with free shipping.
The Gas Key
One common issue with cheap BCGs is a weak or poorly staked gas key. This is why we suggest investing in full auto BCGs built to mil-spec. That’s what we provide with every AR 15 pistol kit and AR 15 rifle kit we sell.
Our most popular AR upper includes a full-auto, chrome-lined BCG.
The gas key is located on top of your BCG. It’s the odd piece that just sticks out from the front of your BCG, held in place by two screws. If those screws loosen, the gas key will wiggle. You can tighten the gas key with a staking tool, or LocTite them as a temporary fix. If this happens, you should consider purchasing a new BCG.
Keeping Your AR Running
The AR 15 is one of the easiest weapons to disassemble and clean, and lucky for you, basically every part can be replaced by your own hands with simple tools. If you clean and maintain your AR 15 consistently, you’ll have a gun that’ll last for decades without fault.