The Right Ar Stock For The Job

The AR stock is a multi-functional component of the firearm that rests against the shooter’s shoulder and anchors the firearm to the shooter’s body. It lets the shooter aim, support and control the firearm, align their eyes with the weapon’s optics, and manage recoil.  

Whether you’re building an AR from scratch or buying one off the shelf, the quality of your experience with your firearm will be directly impacted by having--or not having--the right stock. Luckily, they’re easy to install and you can choose the one that’s best suited for your firearm and how you plan to operate it. With so many different stocks to choose from, we’ve come up with a primer on what features will add value to your individual experience.

length of pull adjustability

By adjusting LOP, the gun is adjusted to the shooter’s frame and eye relief can be set for mounted optics to support different shooting positions and applications. 

LOP is usually changed by sliding the stock closer or further away from the AR’s receiver along the buffer tube. 

Fixed Stocks do not adjust, are very steady, and LOP remains the same unless the butt-pad thickness is changed.  

ADJUSTMENT AND LOCKING MECHANISMS

Levers are common for adjusting LOP by releasing and resetting the lock pin, which holds the stock in the desired position. Some levers are recessed inside the stock’s profile to shield it from snagging, while others include a cutout in the stock’s body to shield the lever and for easy access and adjustment.  In addition, many stocks have an additional manual friction lock to add tension and further secure the stock to the buffer tube, mitigating stock movement.

In general, there are four methods of adjusting LOP and securing your stock on your rifle.  

Some stocks have a Single Tension method to secure the stock to the buffer tube. This method includes a lever with a locking pin to change LOP and maintain the position of the stock on the rifle. There is no additional source of tension to hold the stock in place.

Recessed Lever With Single Tension

For stocks with Active Tension, the user manually activates the lever and moves the stock to the desired position on the buffer tube. When the lever is released, the pin seats in the adjustment hole. To add extra tension that stabilizes the stock on the buffer tube, a manual friction lock must then be closed to create that tension.  

Active Tension, Cutout Lever, Manual Friction Lock Closed
Active Tension, Cutout Lever, Manual Friction Lock Open

For stocks with Passive Tension, additional tension to secure the stock is either automatically released and reapplied when the lever is activated (Dual Tension), or the tension always remains in place (Continuous Tension). In both cases, the shooter does not have the secondary step of opening or closing a separate, manual friction lock. With Dual Tension, when the lever is activated and released, the secondary tension is released and reapplied. With Continuous Tension, the additional tension remains at all times and there is a noticeable sensation and sound of friction as the stock is adjusted.

Passive Tension Method With Dual Tension
Passive Tension Method With Continuous Tension

Fixed Clamp method permanently attaches the stock to the buffer tube using hardware or includes its own buffer tube that attaches to the rifle. It prevents the stock from moving on the tube and is the most secure method of attaching a stock to the rifle.

Fixed Clamp With Hardware
Fixed Clamp With Included Buffer Tube

Some Fixed Clamp stocks are used for precision shooting and provide a very stable platform. They also include knobs and tooled adjustments for LOP.

Fixed Clamp Precision Stock With Adjustment Knobs
Fixed Clamp Precision Tooled Adjustment

Cheek Weld & Comb Height Adjustability

Cheek weld refers to the contact between the shooter’s cheek and comb height refers to the height of the cheek weld above the stock.

Cheek weld and comb height work together to improve shooter comfort and help align the shooter’s eyes with the optic. Stocks may offer flatter or steeper angles to support individual cheek weld, and they can also include different-sized or adjustable cheek risers to increase or decrease the comb height for the shooter. It’s important to have the ability to choose or adjust the size, shape, and angle of the cheek weld and the height of the comb to accommodate the many different facial shapes and personal preferences that exist.

Clip on cheek risers are an efficient way to adjust comb height on carbine stocks. Due to varying charging handle strokes/dimensions and receiver sizes on AR platforms, the clip on risers may block full travel of the charging handle and render the rifle inoperable, particularly if the stock is not fully extended. Please confirm function of your rifle prior to use if adding a clip on cheek riser.

Clip on Cheek RiserTooled Adjustable Cheek RiserTool-less Adjustable Cheek Riser

STOCK Ergonomics

 

Simply put, ergonomics includes any interface or touchpoint between the stock and the shooter. Whether it’s the stock’s size, shape, surface, or the ease of use and logical manipulation of the controls, designing for ergonomics is vital. The result is a stock that comfortably fits the shooter’s individual needs while being intuitive to operate. This enables enhanced employment consistency.

BUTT-PAD

The stock’s butt-pad is a key contributor to individual ergonomics. It can reduce felt recoil because it is the point of contact where most of the firing energy is transferred from the gun to the shooter’s body. The butt-pad’s thickness, angle, shape, and material all act together to change how the butt-pad fits and cushions a shooter, help mitigate muzzle rise, ensure repeatable fit into the shooter’s shoulder, and reduce snagging. Additionally, wearing body armor or any other unique gear may influence the need for a specific butt-pad shape. Some butt-pads are also adjustable in height and cant to more specifically support the body-to-stock interface.  

Butt-pad thickness can increase or decrease the shooter's length of pull, such as with the line of Magpul’s Enhanced and Extended butt-pads. Hybrid butt-pads combine features and shapes from more than one style of butt-pad to increase the overall effectiveness of the butt-pad.

Your Image

Contoured: This hourglass style of butt-pad is designed to fit the shooter by providing a natural curve that seats into the user's shoulder or body armor.

Your Image

Rapid mounting: On the move, easy shouldering. This style of butt-pad supports quick, secure mounting of the rifle. The rolled toe and forward angle allows for faster mounting to a stable position for consistent employment.

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Precision: This style of butt-pad, along with adjustability of the buttstock, provides a more stable shooting platform. In general, precision butt-pads are softer and stay anchored to the shooter’s shoulder for reapable, consistent shots.

Buffer Tube / Receiver Extension

Carbine Buffer Tube Diameter

There are two diameters of carbine buffer tubes (also known as receiver extensions): Commercial and Mil-Spec. Virtually all manufacturers use Mil-Spec tubes on modern rifles, but you should always confirm the buffer tube diameter on your rifle.  


Buffer Tube Length

Common Buffer Tube Lengths

There are a few different buffer tube types and lengths, but most are either carbine- or rifle-length. The most common is the carbine-length buffer tube. Additionally, most stocks only work with rifle or carbine-pattern buffer tubes, although there are exceptions.

Before buying a stock, it’s important to determine what buffer tube you have because it may limit stock options. Some stocks may still fit, but won’t be as compact as desired. Pairing stocks and tubes should always be based on the rifle’s application or the shooter’s goals.

Stock Length

Your ImageCompact
Your ImageCarbine
Your ImageRifle

Compact stocks are generally designed for short weapons for easier handling and maneuvering in confined spaces. Carbine stocks meet a wide range of needs for adjustability and LOP, making them the most common. Rifle stocks provide an extremely stable and repeatable platform, but they are generally not adjustable on the buffer tube.

It’s imperative to know the local, state, and federal laws pertaining to the overall length of your firearm as well as the legality of collapsible stocks in your location, as putting a collapsible stock on some guns may result in a violation of one or more of those laws.   

Materials, strength, durability & WEIGHT

 

Because they’re the part of the firearm that takes the brunt of firing recoil – and tend to be on the receiving end of hard use – AR stocks need to be built from quality materials to ensure strength and durability in even the most demanding situations. Different stocks with different missions also need to be constructed from uniquely different materials to align with the qualities required by that stock’s mission.

Also, too much weight in the firearm can make carrying it a chore and can impact mobility. However, adding greater strength and the ability to handle hard use generally also adds weight to the materials used in construction. As a result, lighter is better to a point, but not at a compromise to the ruggedness of the stock and its ability to stay in one piece and operate effectively.  
 

Storage

 Stock storage allows important items such as batteries to be held onboard the firearm and close at hand. Some stocks have internal storage capability for small items. This storage can be built into the bottom of the stock or in the cheek weld. In the case of cheek-weld storage, this also flattens and widens the shooter’s cheek weld surface area.  

Door Storage
Tube Storage
Butt-pad Storage

Sling-Mounting Options

Most stocks have multiple ways to attach a sling for easier carry and better control of the firearm. A sling loop or footman’s loop provides a slot for a sling to be threaded through. quick disconnect (QD) socket uses a push-button system to attach and detach a sling.

Footmans's Loop

Footman’s Loop: Many rifles come with fixed sling loops either built into the frame or attached to the stock. These are simple, and they don’t require any extra hardware. Some stocks also include a Footman's Loop with M-LOK Slot dimensions, making them compatible with an optional M-LOK QD Sling Mount to add QD capability to the stock.

QD Socket

QD SocketsQD sockets allow slings to be mounted securely--with flexibility and speed in mind--thanks to their strength, simple push-button operation, and ability to connect ambidextrously. Some stocks have empty QD Cups where optional QD Sockets can be installed.

Precision design as a feature

PRS GEN3 Precision-Adjustable Stock

A stock can do many things, but if it doesn’t give a shooter a consistent, stable, solid platform to work from, it doesn’t do them any good downrange. AR stocks must be purposefully built to support repeatable precision by removing shooting variability caused by the stock. This allows the shooter to focus on factors other than the stock that can affect precision and accuracy. Precision stocks offer more adjustments for cheek weld, LOP, and other ergonomics, providing an optimal and completely individualized interface for the shooter. 

Simple Installation & Ease of Use

Simple Installation
Ease of Use

The more complicated a firearm component is, the less likely it will be used, or used correctly. AR stocks should be simple in both design and function. This ensures every stock’s controls and features are intuitively designed and logically placed, allowing even new shooters entering the world of firearms to efficiently and effectively use the variety of stocks for the AR platform.   

VALUE

Value, performance, and quality are all important factors in choosing a stock. More high-quality features may increase the stock's price, but may not be important to different shooters. Precision stocks are extremely specialized due to their adjustability and come at a much higher cost. Each stock is designed and optimized for a specific need, mission, and feature set. 

MOE PR Carbine Stock

 Key Performance Features. Value Pricing

DT-PR Carbine Stock

Added Features, Greater Adjustability and Functions. Increased Price Point

PRS GEN3

Premium Features, Adjustability, Materials and Function. Highest Relative Price Point

Color

Different colors provide shooters with options in their build, ranging from blending into their background and camouflage to simple taste, because not all black guns are actually black guns.