What Are The Types Of AR Buffer Tubes:
- AR15 carbine – 7” long on the inside
- AR10 carbine which is the same as an A5 buffer tube – 7.75” long on the inside
- People use the terms AR10 buffer tube and A5 buffer tube interchangeably
- AR10/AR15 fixed stock buffer tube – the fixed buffer tube is the same for both types of guns
- AR15 framed rifle with a rifle or fixed stock buffer tube needs an RB5001 AR15 rifle buffer and an AR15 or .223 rifle buffer spring. This is true for any caliber if it has the fixed stock buffer tube
- AR10 framed rifle with a rifle or fixed stock buffer tube needs an RB5006 AR10 rifle buffer and an AR10 or .308 rifle buffer spring. This is true for any caliber in an AR10 framed gun if it has a fixed stock buffer tube. So, .308/7.62, 6.5 Creedmoor, .260 Rem, .243, .338 Federal, any of them.
- AR15 framed guns with a carbine buffer tube and a locking gas system (direct gas impingment or piston driven) will need a 3.25” buffer. So any of the many AR15 calibers - .223/5.56, .300 BLK, 6.8 SPC, 6.5 Grendel, 7.62x39, .350 Legend, .204, .450 Bushmaster, .458 SOCOM, etc. will all use that size buffer if it has a carbine buffer tube. But they may need a different weight buffer or a different buffer spring strength to run right. That is why we have a lot of spring weights for AR15 carbines and we have the RB5000, RB5000L (Light Model), and RB5000HP (High Pressure) that are made to serve these different requirements.
- AR10 framed guns with an AR10 or A5 length carbine buffer tube will use a 3.25” buffer, model RB5005 and an AR10 carbine or .308 carbine buffer spring.
- AR10 framed guns with an AR15 carbine buffer tube will need the shorty, 2.5” AR10 carbine buffer, model RB5004 and an AR10 carbine or .308 carbine buffer spring. A lot of manufacturers building AR10 framed guns (probably most of them) are using these shorter buffer tubes because they are more available and usually cheaper, and this requires the shorter buffer.
- 9mm or other Pistol Caliber, blow-back operated AR15s such as .40 cal or .45 ACP have a shorter bolt, so the bolt doesn’t need to travel as far to get behind the bolt catch. This is why we make our 9mm buffers 4.0” long. If someone uses a longer AR10/A5 carbine buffer tube, then they need a spacer or weight to make up the difference so the bolt stops where they need it to.
How do I change the buffer tube on my ar 15?
- Ensure the firearm is unloaded: Double-check that the AR-15 is unloaded, and there is no round in the chamber. Remove the magazine if one is present.
- Separate the upper and lower receivers: Push the rear takedown pin and the front pivot pin on the lower receiver to detach the upper receiver from the lower receiver. Pull the pins out from one side and open the rifle. You may completely separate the upper and lower by pulling the pins out entirely.
- Remove the buffer and buffer spring: Locate the buffer tube, which houses the buffer and buffer spring. Press down on the buffer retainer (a small pin) located near the front end of the buffer tube. This will release the buffer and buffer spring. Slowly and carefully pull the buffer and spring out of the buffer tube.
- Remove the stock: Depending on the type of stock you have, there may be a lever or a pin you need to depress to slide the stock off the buffer tube. Once the stock is removed, set it aside.
- Remove the castle nut and end plate: Using an armorer's wrench or a similar tool, loosen the castle nut by turning it counterclockwise. Once it's loosened, slide it forward along the buffer tube. Then, carefully slide the end plate forward, being mindful of the spring-loaded detent and spring underneath the end plate that hold the rear takedown pin in place.
- Unscrew the buffer tube: Hold the lower receiver firmly and turn the buffer tube counterclockwise to unscrew it from the lower receiver. As you reach the end of the threads, be cautious of the buffer retainer and buffer retainer spring, as they can also fly out when the buffer tube is fully unscrewed.
- Install the new buffer tube: Screw the new buffer tube into the lower receiver, ensuring that it is properly aligned. The buffer retainer hole should be visible when the tube is screwed in enough. Insert the buffer retainer and buffer retainer spring, and continue to screw in the buffer tube until it holds the buffer retainer in place.
- Reinstall the end plate and castle nut: Slide the end plate back against the lower receiver, taking care to align the rear takedown pin detent hole and spring. Then, slide the castle nut back and hand tighten it. Use the armorer's wrench to snug the castle nut, but do not overtighten it.
- Reinstall the stock: Slide the stock back onto the new buffer tube, engaging the locking mechanism.
- Reassemble the rifle: Reattach the upper and lower receivers by aligning the pivot pinholes and takedown pinholes, and then push the pins back in to secure the two halves.
- Function check: Perform a function check by working the charging handle, dry firing, and checking the safety selector to ensure everything is working correctly. If everything seems to be functioning properly, your buffer tube replacement is complete.
Are ar 15 and ar 10 buffer tubes the same?
AR-15 and AR-10 buffer tubes are sometimes the same, but are not always the same. While they may appear similar, there are key differences between them. The AR-10 carbine buffer tube is 3/4" longer and than the AR-15 buffer tube. This is because the AR-10 framed guns are designed around a larger cartridge (.308/7.62mm NATO) resulting in a longer receiver and a longer bolt carrier. This longer bolt carrier and longer stroke of the bolt carrier to feed and eject the longer cartridge results in more room being needed in the buffer tube. So for carbine buffer tubes, if an AR15 length buffer tube is used, which is 7" on the inside, this requires a shorter 2.5" buffer on an AR10. If an AR-10 carbine tube is used, this allows for a 3.25" buffer to be used. Some AR-10 framed guns are made with AR15 carbine buffer tubes and some are made with AR10 carbine buffer tubes, which can be a bit confusing. The main thing to remember is that the length of the buffer tube is what changes the length of the buffer needed.
It is important to use the correct buffer tube for your specific rifle platform to ensure proper function and reliability. If you use a 3.25" buffer in an AR10 with an AR15 carbine tube, it will short stroke the action and will not feed or eject properly. If you use a 2.5" buffer in an AR10 carbine tube, the gun will over-stroke (the carrier will travel too far) and the carrier could impact the rear of the lower receiver which could damage it.
Are all ar 15 buffer tubes the same?
Not all AR-15 buffer tubes are the same. There are two main types of AR-15 buffer tubes: mil-spec and commercial-spec. These two types differ slightly in their dimensions, primarily in the outer diameter of the tube and the threading.
Mil-spec buffer tubes have a slightly smaller diameter (1.148 inches) and finer threads than commercial-spec buffer tubes, which have a diameter of 1.168 inches. Additionally, the rear end of a mil-spec buffer tube is flat, whereas a commercial-spec buffer tube has a slanted rear end.
It is essential to know which type of buffer tube your AR-15 uses because buttstocks designed for one type will not properly fit the other. When purchasing a new buttstock or buffer tube, ensure that it is compatible with your specific AR-15 configuration. Mixing mil-spec and commercial-spec components can lead to a loose fit, instability, and potential damage to your rifle.
Due to the broad popularity of the mil-spec sized buffer tubes and the now rare use of the commercial spec buffer tubes, we only carry mil-spec sized buffer tubes.