Building an AR-15 style rifle with a gun kit? There are lots of small gun parts you’ll need to get familiar with; roll pins, takedown pins, a whole lot of springs, nuts, and others, too.

Some last pretty much the entire life of the gun, as long as it is well cared for. Others are prone to failure long before you might expect.

Here are some of the most common among them. It’s worth it to get spares of these gun parts when buying a kit so you can make easy replacements when the time comes.

● Extractor
The extractor is a tiny, hook-shaped piece, integrated with the bolt, which latches onto the rim of the cartridge and pulls it free of the chamber after the bolt unlocks and cycles back after firing.

They can crack, chip, and break, making it impossible for them to engage the rim of the cartridge. In addition to normal wear that can make extraction unreliable, what can also happen is the extractor spring can wear out, too.

Either way, having a spare few extractors and springs in your range bag or home at the bench can make sure you’re ready when repairs are needed.

● Gas tube
Your rifle’s gas tube has a flared end that creates a tight seal between it and the bolt carrier group’s gas key.

Over time, this flared end can get pounded flat from repeatedly being struck by the BCG. When this happens, it can let gas leak, and over time, cycling time can be sluggish, or unreliable altogether.

If that’s happening, it’s time to replace the gas tube. Also, but less commonly, the roll pins that hold the block and tube together can walk loose, necessitating replacement.

● Bolt gas rings
The gas rings are about the most abused part on the AR. Over time, they can wear out and let gas leak, which will hinder cycling.

To check whether or not the bolt’s gas rings are in good shape, pull the bolt forward from the carrier and set the carrier on a flat surface, with the bolt facing down.

If the weight of the carrier alone is enough to force it down on the bolt, then you need to replace your gas rings.

(Also, other parts of the bolt, such as the cam pin holes or locking lugs can also wear and fail, so keep an eye on these, too.)

● Firing pin
Like the gas tube, the firing pin takes it on the chin each time you pull the trigger. Firing pins, which are hardened, can crack or break after prolonged use. You can expect somewhere in the area of 10,000 to 15,000 rounds from most firing pins – although one could last longer.

Either way, when you pull the trigger and hear a “click,” consistently, the rifle won’t fire, and you know it isn’t the hammer spring, check inside the bolt for a snapped firing pin.

● Hammer spring
The hammer spring provides the power for the hammer to strike the pin, which strikes the primer, igniting it. When the hammer spring fatigues, it will either snap, or will not provide enough power to the hammer to strike the firing pin. This will cripple the rifle until the spring is replaced.

● Buffer spring
Buffer springs are actually very long lasting, as they are compression springs, but all springs can fatigue and these are no exception. If you notice your bolt carrier group isn’t returned to battery after the rest of the cycle is complete, it could be that the buffer spring has started to take a turn towards the south. In that instance, replace it.

Get Spare Gun Parts with Your AR15 Kit
Whether you’re in need of a specific gun part or just wanted to get started with a build using an AR15 kit, you can find what you need online at SARCO, Inc. They have, in fact, one of the widest collections of gun parts on the web, and very knowledgeable staff. Get in touch with them if you need help finding the part you’re looking for.

For more information about Pistol Frame and Guns Parts Kits Please visit: Sarco Inc.