CMMG AR Pistol Receiver Extension Kit: The Core Foundation for Your AR Pistol Build

For any enthusiast embarking on the journey of building a new AR pistol or upgrading an existing one, selecting the right foundational components is paramount. The CMMG AR Pistol Receiver Extension Kit offers a critical solution, providing the essential elements needed to complete your lower receiver group with confidence and reliability. This kit is specifically engineered to integrate seamlessly with your choice of lower parts kit, transforming a stripped lower into a fully functional and dependable AR pistol platform.

What is an AR Pistol Receiver Extension Kit and Who Needs It?

An AR pistol receiver extension kit, often referred to as a "buffer tube kit" for AR pistols, is a collection of components that work in concert to manage the recoil and facilitate the cycling of your firearm. Unlike standard carbine or rifle buffer tubes, pistol receiver extensions are designed to accommodate the unique requirements of AR pistols, which typically do not feature a shoulder stock.

This kit is an indispensable asset for:

• First-time AR Pistol Builders: If you're starting with a stripped AR lower receiver and an AR pistol barrel, this kit provides the crucial parts to get your lower operational.
• Experienced Customizers: For those looking to fine-tune their AR pistol's performance or replace worn components, the CMMG kit offers a reliable upgrade path.
• DIY Firearm Enthusiasts: If you enjoy assembling your own firearms and ensuring every component meets high standards, this kit provides a solid starting point for the lower.
• Anyone Seeking Reliable AR Pistol Functionality: Proper buffer system components are essential for reliable cycling, reducing felt recoil, and maintaining accuracy.

Addressing Common Questions About AR Pistol Builds

• "What parts do I need to finish my AR pistol lower?" Beyond a lower parts kit (LPK) which includes components like the trigger group, safety selector, and pistol grip, you absolutely need a receiver extension kit. The CMMG kit provides the receiver extension, buffer, and spring – all vital for the firearm's operation.
• "How does an AR pistol buffer tube differ from a carbine buffer tube?" While both house the buffer and spring, AR pistol receiver extensions are typically shorter and lack the provisions (like multiple adjustment positions) for mounting a traditional adjustable carbine stock. They are designed to be used without a stock to comply with pistol classifications.
• "Why is the buffer system so important for an AR pistol?" The buffer and spring regulate the speed at which the bolt carrier group (BCG) moves rearward and forward during the firing cycle. A properly tuned system ensures consistent extraction, ejection, and feeding, minimizing malfunctions and contributing to a smoother shooting experience.

Unpacking the CMMG AR Pistol Receiver Extension Kit: Precision Engineered Components

The CMMG AR Pistol Receiver Extension Kit (MPN: 55CA65A) is a testament to CMMG's commitment to quality and functional design. It includes three core components, each meticulously crafted to ensure optimal performance for your AR pistol.

1. CMMG Pistol Receiver Extension (Buffer Tube)

The receiver extension is the backbone of your AR pistol's recoil system. CMMG's pistol receiver extension is built to exacting standards, ensuring a precise fit with Mil-Spec lower receivers.

• Durability: Constructed from robust aluminum, typically 6061-T6 or 7075-T6 aircraft-grade aluminum, and often hard-coat anodized for superior corrosion resistance and wear protection. This ensures the component can withstand the rigors of repeated firing and harsh environments.
• Design: Specifically designed for AR pistols, it provides the necessary internal space for the buffer and spring without the external features required for a shoulder stock, which is critical for maintaining the pistol classification of the firearm.
• Functionality: It provides a sturdy mounting point for the end plate and castle nut, securely attaching the buffer system to the lower receiver. The interior is precisely machined to allow for smooth, unimpeded travel of the buffer.

2. Carbine Buffer Assembly

The buffer is a weighted component that travels within the receiver extension. Its primary role is to absorb kinetic energy and manage the recoil impulse.

• Weight Optimization: CMMG typically includes a standard carbine buffer, which is a common and effective weight for a wide range of AR pistol configurations. This standard buffer often strikes an excellent balance, offering reliable operation with various ammunition types and gas system setups.
• Recoil Management: By controlling the speed of the bolt carrier group, the buffer helps to smooth out the firearm's cycling, leading to less perceived recoil and a more comfortable shooting experience. This can be particularly noticeable on lighter AR pistol builds.
• Cycling Consistency: A correctly weighted buffer prevents the bolt carrier group from impacting the rear of the receiver extension too forcefully or returning too quickly, which can lead to issues like premature wear or failures to feed.

3. Carbine Action Spring

The action spring, often called a buffer spring, works in conjunction with the buffer to cycle the firearm.

• Material and Tension: CMMG's action springs are made from high-quality spring steel, designed to provide consistent tension and durability over thousands of compression cycles. The consistent tension is crucial for reliable bolt return and proper feeding of rounds from the magazine.
• Reliable Cycling: As the bolt carrier group moves rearward, compressing the spring, the spring stores energy. This stored energy is then released to push the bolt carrier group forward, stripping a new round from the magazine and chambering it. A quality spring ensures this process is smooth and dependable.
• Longevity: A robust spring resists "spring set" or weakening over time, maintaining its performance characteristics through extensive use.

Why Choose CMMG for Your AR Pistol Build? The Mark of Quality and Performance

CMMG has established itself as a reputable name in the firearms industry, known for manufacturing high-quality AR platform components and complete firearms. When you select the CMMG AR Pistol Receiver Extension Kit, you're not just buying parts; you're investing in a system designed for performance and reliability.

• Trusted Engineering: CMMG's products are developed with meticulous attention to detail and rigorous quality control. This means each component in the kit meets strict specifications, ensuring proper fit, form, and function.
• Enhanced Reliability: The synergy between CMMG's pistol receiver extension, carbine buffer, and action spring is optimized to provide consistent and dependable cycling, minimizing common malfunctions like failures to feed or extract. This translates directly into a more enjoyable and trustworthy shooting experience.
• Durability and Longevity: By utilizing premium materials and manufacturing processes, CMMG ensures their components can withstand the stresses of high-volume shooting and maintain performance over the long term. This durability makes it a smart investment for any serious builder.
• Seamless Integration: The kit is designed to be fully compatible with standard Mil-Spec AR lower receivers, making it a straightforward choice for almost any AR pistol lower build. This eliminates compatibility headaches often associated with aftermarket parts.
• Foundation for Future Performance: A strong foundation is crucial for any build. By starting with a CMMG receiver extension kit, you lay the groundwork for a stable, high-performing AR pistol that can be further customized with other premium components as your needs evolve.

Real-World Applications and Use Cases

The CMMG AR Pistol Receiver Extension Kit is vital for a variety of AR pistol applications, from range use to personal defense.

• Sporting and Recreational Shooting: For enthusiasts who enjoy precision shooting or plinking at the range, a reliable buffer system ensures consistent performance shot after shot, allowing for better accuracy and more enjoyable practice sessions.
• Compact Personal Defense Firearms: AR pistols are increasingly popular for home defense due to their maneuverability in confined spaces. A dependable buffer system is non-negotiable in a self-defense firearm, ensuring it operates flawlessly when it matters most.
• Backpacking and Vehicle-Based Firearms: The compact nature of AR pistols makes them suitable for transport. Ensuring robust operation with the CMMG kit means your firearm is ready for use whenever and wherever you need it, within legal parameters.
• Custom Builds and Thematic Projects: Builders often undertake projects with specific aesthetics or performance goals. This kit provides a robust, standard platform from which to launch highly customized AR pistol endeavors.

Installation and Compatibility Notes

Installing the CMMG AR Pistol Receiver Extension Kit is a fundamental step in completing your lower receiver. While specific detailed instructions should always come with your lower receiver or be found in a reputable armorer's manual, here’s a general overview of its place in the build:

1. Lower Receiver Preparation: Ensure your stripped lower receiver is clean and ready for assembly.
2. Receiver Extension Mounting: The CMMG pistol receiver extension threads directly into the rear of your AR lower receiver.
3. End Plate and Castle Nut: An AR-15 end plate slides onto the receiver extension, followed by a castle nut. These secure the receiver extension to the lower receiver. Proper torque and staking of the castle nut are crucial for long-term reliability.
4. Buffer and Spring Insertion: Once the receiver extension is securely mounted, the carbine action spring and carbine buffer are inserted into the tube.
5. Lower Parts Kit Integration: With the receiver extension kit installed, you can proceed with installing your chosen lower parts kit, which typically includes the trigger group, safety selector, magazine release, and pistol grip.

Compatibility: The CMMG AR Pistol Receiver Extension Kit is designed for maximum compatibility with Mil-Spec AR-15 lower receivers. Its standardized dimensions ensure a hassle-free fit, making it a go-to choice for builders working with various brands of AR lower receivers.

The CMMG Commitment: A Trusted Partner in Your Build

CMMG's dedication to innovation and quality is evident in every component they produce. This receiver extension kit is no exception, embodying the precision engineering and robust construction that builders have come to expect from the brand. Whether you are assembling your very first AR pistol or adding another custom build to your collection, relying on CMMG for these critical components provides peace of mind.

For those ready to take the next step in their AR pistol build, the CMMG AR Pistol Receiver Extension Kit is an essential investment. It represents a commitment to reliability, performance, and durability, ensuring that your firearm operates smoothly and consistently. These high-quality CMMG products, including this essential kit, are readily available at DEGuns, offering a trusted source for all your firearm component needs. Equip your AR pistol with the best foundation, and experience the difference CMMG quality makes.

Product Specifications

Feature	Detail
Brand	CMMG
Model	Receiver Extension Kit
Firearm Fit	AR-Platform
Color	Black
Firearm Type	AR Platform
SKU	96790
MPN	55CA65A
UPC	815835017099