Understanding Pistol Buffer Tube Lengths: A Comprehensive Guide


When it comes to building or customizing an AR-15 pistol, one of the crucial components that demand attention is the buffer tube. The pistol buffer tube plays a pivotal role in the functioning of the firearm, affecting not only its performance but also its overall aesthetics. In this article, we will delve into the nuances of pistol buffer tube length, exploring its significance, variations, and how it can impact your AR-15 pistol.

The Basics:

The buffer tube, also known as the receiver extension, is a metal tube that attaches to the rear of the AR-15 lower receiver. Its primary function is to house the recoil buffer and buffer spring, which work together to absorb and manage recoil during the firing cycle.

In the realm of AR-15 pistols, the buffer tube serves a dual purpose – providing a mounting point for the pistol brace and serving as a housing for the recoil system. Pistol buffer tubes differ from those used on traditional rifles in that they lack the space for a rifle stock and are designed to accommodate a pistol brace instead.

Pistol Buffer Tube Lengths:

Pistol buffer tubes come in various lengths, and the choice of the appropriate length is crucial for both functionality and legal compliance. The two main lengths you will encounter are the Mil-Spec and the Commercial buffer tubes.

Mil-Spec Buffer Tube:

The Mil-Spec (Military Specification) buffer tube is the standard size used by the military and is widely adopted in the AR-15 platform.

The length of the Mil-Spec buffer tube is approximately 7 inches.

Mil-Spec tubes have a slightly smaller diameter, and stocks and braces designed for Mil-Spec tubes are not compatible with Commercial tubes.

Commercial Buffer Tube:

Commercial buffer tubes are slightly larger in diameter compared to Mil-Spec tubes.

They often have a slanted back end and a varying length, usually around 7.25 inches.

While less common, some manufacturers offer Commercial buffer tubes for those who prefer this design.

Choosing the Right Length:

Selecting the appropriate pistol buffer tube length depends on various factors, including personal preference, intended use, and the type of pistol brace you plan to install. Consider the following:

Comfort and Ergonomics:

The length of the buffer tube can impact the overall ergonomics and comfort of the AR-15 pistol.

Personal preference plays a significant role, and it’s advisable to handle firearms with different buffer tube lengths to find the one that feels most comfortable for you.

Legal Considerations:

It’s crucial to be aware of local laws and regulations regarding AR-15 pistols and brace configurations.

Some jurisdictions may have restrictions on the overall length of an AR-15 pistol, including the buffer tube and brace.

Compatibility with Braces:

Ensure that the buffer tube you choose is compatible with the pistol brace you intend to use.

Some braces are designed specifically for Mil-Spec tubes, while others may be compatible with both Mil-Spec and Commercial tubes.


The pistol buffer tube length is a critical consideration when building or customizing an AR-15 pistol. Understanding the differences between Mil-Spec and Commercial tubes, along with the implications of various lengths, will enable you to make an informed decision based on your preferences and legal requirements. Remember to always stay informed about local firearm regulations and consult with knowledgeable professionals if needed, ensuring a safe and compliant AR-15 pistol configuration.