4 Best Mil Spec Buffer Tube Options

While most mil spec buffer tubes all function the same, but the buffer spring and buffer weight matters a lot more for a high performance AR15 rifle. 

So here are the 4 best mil spec buffer tube kits for AR15.

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Top 3 Picks

Geissele Super Duty

  • Long service life
  • Improved spring harmonics

PSA AR15 Buffer

  • Affordable
  • Fluted

Strike Industries Advanced

  • Super lightweight
  • Improved aesthetics

Why Upgrade Buffer

Buffer tube kits are crucial because the buffer weight, combined with the spring's tension, absorbs the force of firing a round. This helps manage recoil and cycle the rifle. Different weights and spring tensions can alter the rifle's feel and characteristics. The buffer tube also physically connects the buttstock to the rifle.

The buffer tube houses two key components – the buffer and the action spring. The spring decompresses into the buffer tube, and the buffer sits inside the spring, making contact with the bolt when attached to the rifle.

One of the simplest ways to fine-tune your ejection angle is with a lighter (or heavier) buffer. When the rifle is fired, the bolt slides back from the gas expulsion, hitting the buffer, and compressing the spring inside the buffer tube.

This compression stores energy in the spring, which expands once the bolt has traveled rearward enough to allow the spent casing to be ejected. The spring's expansion is what moves the bolt back into place, chambering the next round.

The balance between cartridge energy and buffer is what helps a gun run smoothly and eject brass consistently. Upgrading or updating your buffer tube can help you get your gun back in balance.

Top Mil Spec Buffer Tube Kits

Geissele Super 42 Braided Buffer Spring & Buffer

Geissele Super 42 Braided Buffer Spring

This exceptional braided buffer spring operates at only ~35% of its maximum stress load to endure longer service life, and it eliminates the "twanggg" sound typically associated with standard AR15s. 

The incorporation of braided wire enhances weapon cycling performance and augments bolt return force, guaranteeing flawless round chambering even in the presence of dirt or steel case ammunition.

Palmetto State Armory Classic Lower Build Kit

Palmetto State Armory Classic Lower Build Kit

Palmetto State Armory offers more than just buffer kits. They have a wide range of complete lower build kits, which include buffer tubes, buffers, and components, as well as buttstocks, grips, and more.

They come in various colors and pistol options, providing an easy way to ensure you're getting compatible components all at once.

If you want to build a new rifle, here is a great deal to get all in one package.

Aero Precision AR-15 Carbine Buffer Kits

Aero Precision AR-15 Carbine Buffer Kits

Aero Precision offers a carbine length AR-15 buffer kit with the option of choosing an H, H2, or H3 buffer. This kit includes a buffer tube, buffer, buffer spring, endplate, and castle nut.

It's also available in an enhanced version with Carrier Support Extensions that prevent carrier tilt and minimize wear. When paired with their lower parts kit, you get a high-quality build that's designed to work well together.

Brownells AR-15 Rifle Buffer Tube Kit

Brownells AR-15 Rifle Buffer Tube Kit

The Brownells AR-15 rifle length buffer tube kit is mil-spec and will fit all rifle length buttstocks. It's made from mil-spec 7075 aluminum and features a matte black hardcoat anodized finish, giving it that true black rifle feel.

Luth-AR AR-15 Mil-Spec Carbine Buffer Package

Luth-AR AR-15 Mil-Spec Carbine Buffer Package

Luth-AR offers a mil-spec or commercial carbine length buffer tube kit for the flexibility to accommodate either stock on a rifle build. It comes complete with the buffer tube, lock plate, buffer, and spring.

Luth-AR makes some of the best buttstocks available, and these can be purchased as a bundle with the correct buffer assembly. No muss, no fuss.

What to Look for in a Quality Mil Spec Buffer Tube Kit

Mil-Spec vs Commercial Buffer Tubes


There are two standard types of buffer tube kits: mil-spec and commercial

Mil-spec buffer tubes are built two-hundredths of an inch smaller than a commercial tube. This slight change in diameter means the two are not interchangeable. The buttstock has to match the tube size, or it will not assemble correctly.

Mil-spec buffer tubes are forged from 7075 T6 aluminum, known for its enhanced strength and resistance to stress. In contrast, commercial buffer tubes are made from 6061 T6 billet aluminum, which possesses lower strength and durability despite its advantage of easier weldability.

Buffer Weight Options

Mil-spec buffer tubes, which are smaller by two-hundredths of an inch compared to commercial tubes, are built in a manner that does not allow interchangeability between the two. This is due to the crucial requirement of matching the tube size with the buttstock for proper assembly.

Geissele buffer weight chart

Referenced Geissele

  • H1 is typically recommended for 18" and above barrel length
  • H2 is typically recommended for 14.5" to 16" barrel with carbine or mid-length gas system
  • H3 is typically recommended for 10.5" short barrel

Rifle buffers are much longer and designed to be used in standard buffer tubes with fixed stocks. Carbine buffers are shorter, used in carbine-length buffer tubes, and are designed to accommodate adjustable stocks. Most of the time, you'll want a carbine buffer.

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