Understanding the Colt Stripped Upper Receiver
What is a Stripped Upper Receiver?
The stripped upper receiver, often referred to as the “upper” in the AR-15 world, is essentially the backbone of your rifle’s operating system. It’s the portion of the firearm that houses the bolt carrier group, barrel, and handguard. The term “stripped” indicates that the receiver is sold without internal components such as the forward assist, dust cover, or charging handle, leaving the builder with the freedom to select and install these parts according to their preferences.
The primary function of the upper receiver is to provide a secure housing for the barrel and the bolt carrier group, ensuring that the weapon cycles reliably. It’s also the platform for mounting the sights, optics, and handguards, effectively determining the overall ergonomics and customization possibilities. This is why the choice of an upper receiver is so important.
Key Features and Characteristics
Colt has consistently used high-quality materials in the construction of its upper receivers. Typically, these receivers are manufactured from 7075-T6 aluminum alloy, renowned for its strength-to-weight ratio. This material provides excellent durability, able to withstand the stresses of repeated firing and harsh environmental conditions. While forging and billet manufacturing processes both exist for upper receivers, Colt receivers are often forged. This process involves using intense pressure to shape the aluminum, resulting in increased strength and resistance to cracking.
Identifying a genuine Colt upper receiver is vital, especially when navigating the market for used or aftermarket parts. The discerning eye should look for several key markings. The most prominent is the “C” forge mark, often stamped near the charging handle channel. This mark, an essential identifier, signifies that the receiver was manufactured by a reputable forge, which, in many instances, is consistent with Colt’s rigorous quality standards. Other critical markings include the “M4” or “A” designation, indicating the specific model and configuration. Additionally, many Colt uppers feature the “keyhole” or “square” marking, located on the side of the receiver, near the front. This symbol, while varying slightly over time, is another indicator of Colt origin. Different eras of Colt production boast distinct markings; researching these variations can help determine the receiver’s manufacturing timeframe. These markings, along with the overall fit and finish, are clues that authenticate the component and, in turn, lend an increased value to the end-user.
Historical Significance and Branding
Colt’s branding is a crucial part of its identity, and the company has a history of consistent quality control. Colt’s reputation goes beyond the reliability of their products; it is tied to a sense of history. Owning a Colt-marked part offers a tangible link to a rich legacy.
Colt Stripped Upper Receiver Variations and Identification
Flat-Top Upper Receivers
One of the most prevalent types is the flat-top upper receiver. This design features a Picatinny rail on the top surface, allowing for easy attachment of optics, sights, and other accessories. The flat-top receiver’s popularity stems from its versatility; it lets the user customize the rifle’s sighting system, from iron sights to modern red dot optics and magnified scopes. These uppers will typically bear the “M4” markings, signaling their compatibility with various accessories and barrel configurations.
Carry Handle Upper Receivers
Conversely, there is the carry handle upper receiver. These receivers feature an integrated carry handle, with an iron sight system built in. This design harkens back to the original M16 rifles. While this variant offers a classic aesthetic and a fixed aiming system, the carry handle design limits the attachment of certain optics. While these designs are not as commonly manufactured, they hold historical significance, especially for those seeking to recreate a classic M16 or early AR-15 style rifle.
Identifying Colt from Other Manufacturers
The key to successfully building or restoring an AR-15 using a Colt upper receiver is recognizing the crucial markings that help identify its authenticity and origin. Comparing a potential Colt upper to verified examples, examining the shape of the markings, and assessing the overall finish can help you determine whether a receiver is a genuine Colt part. The fit and finish of a Colt upper receiver are generally excellent, with crisp edges and a smooth surface. These observations can act as key indicators that suggest a genuine Colt offering.
Building with a Colt Stripped Upper Receiver
Component Compatibility
Once you’ve chosen your Colt stripped upper receiver, the next step is to begin building your AR-15. This process allows the owner to tailor the rifle to their precise needs and wants.
Component compatibility is paramount. The barrel is the heart of the firearm, so selecting one that is compatible with your Colt upper receiver is essential. Ensure that the barrel extension matches the upper receiver’s feed ramps. Also, take a look at the gas system length. Correct gas system length ensures reliability and optimal functionality.
Next, you will need to consider the bolt carrier group (BCG), the working mechanism that manages the loading, firing, and extraction process. The BCG must fit your upper receiver and function correctly with the barrel you have selected. Proper headspacing, or the fit between the bolt and the chamber, is an especially critical factor in building your AR-15.
The handguard is another key component to consider, as it not only protects your hands from the barrel heat but also serves as a mounting platform for accessories. Several handguard types are available, from free-floating options to those that attach directly to the barrel nut. If you are building a flat-top, make sure the handguard is compatible with the Picatinny rail.
Assembly Process
The assembly process can be broken down into distinct steps. Begin by installing the barrel, tightening the barrel nut to the manufacturer’s specifications, using the correct tools. Next, install the gas block and gas tube, carefully aligning the gas tube with the gas key on the bolt carrier group. Finally, install the forward assist, dust cover, and charging handle. Once these components are in place, you can then install your handguard. Torqueing all components to the manufacturers’ specified values is essential for overall safety and proper function.
Advantages and Disadvantages of Colt Stripped Upper Receivers
Pros
Choosing a Colt stripped upper receiver has several advantages, making it an appealing choice for both novice and experienced AR-15 builders.
Colt’s reputation for quality and durability is well-earned. The use of high-quality materials and stringent manufacturing processes results in an upper receiver that can withstand the rigors of regular use. In most cases, these upper receivers will function flawlessly.
The historical significance of Colt cannot be overstated. Owning a Colt-marked component is an investment in a piece of firearms history, especially in the case of models with specific markings or those from certain eras. This can increase the value of your rifle, if you desire to sell it in the future.
The value of a Colt upper receiver is more than just about the name; it is also about long-term reliability and functionality. When carefully installed and maintained, your rifle will be able to withstand the stresses of regular use.
Cons
There are also some considerations associated with choosing a Colt upper receiver. The price of Colt components tends to be higher than some other manufacturers, due to their reputation and brand recognition. The availability of specific Colt upper receivers can sometimes be limited, particularly older or rare models.
Finally, the market for AR-15 parts is highly competitive. While Colt remains a dominant force, other manufacturers offer high-quality upper receivers that may offer similar features at a lower price point. Researching all options to determine the value of the market is recommended.
Maintenance and Care
Cleaning
Proper maintenance is crucial for keeping your Colt stripped upper receiver in optimal condition and ensuring its long-term functionality.
Regular cleaning is essential. After each shooting session, disassemble your upper receiver and clean it thoroughly. Use a quality solvent to remove powder residue and carbon buildup from the bolt carrier group, chamber, and bore. Inspect the receiver for any signs of wear or damage.
Regularly inspect the upper for wear and any damage. Also, be sure to lubricate all moving parts with a gun oil designed to resist high temperatures. A well-lubricated upper will cycle smoothly and reliably.
Storage
Proper storage is equally important. When storing your upper receiver for extended periods, clean it, apply a thin coat of oil, and store it in a dry, temperature-controlled environment. A safe or gun case is recommended. Preventing moisture buildup can help prevent corrosion.
Conclusion
The Colt stripped upper receiver remains a cornerstone of the AR-15 world, representing the history, innovation, and commitment to quality that defines the Colt name. From its robust construction to its historical legacy, a Colt upper receiver is more than just a component; it’s a symbol of American firearm craftsmanship. Building your own AR-15 with a Colt stripped upper receiver provides a unique opportunity to create a personalized rifle, steeped in tradition and designed to meet your specific needs. Whether you are a seasoned shooter or new to the world of AR-15s, choosing a Colt upper is a decision that speaks to quality, performance, and a rich heritage. The experience provides the owner with a rifle that feels like it is truly their own. Consider joining a gun building community, and discover more about these interesting pieces of machinery.
The Colt stripped upper receiver provides a solid foundation for any AR-15 build. When you carefully choose your components and put them together, the result will be a high-quality rifle.
