Understanding Full-Auto AR-15s
What is “full auto”
The term “full auto” in the context of firearms refers to the weapon’s ability to fire continuously as long as the trigger is depressed and ammunition is available. This is distinct from “semi-automatic,” where the weapon fires one round per trigger pull, and “burst fire,” where a pre-set number of rounds (usually two or three) are fired with each trigger pull. A full-auto firearm, once the trigger is squeezed, will continue to cycle, ejecting spent casings and chambering fresh rounds at an incredibly rapid pace until the trigger is released or the ammunition is exhausted.
How the AR-15 Platform Works
The fundamental principle of the AR-15 platform remains the same whether it is semi-automatic or full-automatic: the utilization of gas to cycle the action. When a round is fired, the high-pressure gas from the explosion is tapped from the barrel and directed back into the bolt carrier group (BCG). This gas pressure drives the BCG rearward, extracting the spent casing and ejecting it. The BCG then springs forward, stripping a new round from the magazine and chambering it, ready for the next firing cycle. The critical difference is how this cycle is controlled to enable continuous firing.
Historical Context
The AR-15, as a design, has evolved. From its initial development, full-auto versions were conceived and produced. These designs reflect the military and law enforcement roles that the AR-15 was intended to fulfill. As these designs developed, so did the understanding of how to produce the full-auto operation. The basic underlying mechanism remains the same: harnessing the energy of the fired round to repeatedly load and fire until the trigger is released or the ammunition is exhausted. The parts that dictate this behavior are essential, as we will explore next.
Essential Full-Auto AR-15 Parts
The Auto Sear (or Auto Sear Trip)
The auto sear is arguably the heart of the full-auto system. Its purpose is to release the hammer to strike the firing pin and ignite the primer of the next round without the need to release and re-depress the trigger. In a semi-automatic AR-15, the disconnector (a small part within the trigger assembly) catches the hammer after the bolt carrier group cycles, preventing it from being immediately released. The trigger must be released and then pulled again to overcome the disconnector and release the hammer for the next shot.
The auto sear, however, bypasses the disconnector. When the bolt carrier group moves forward, it depresses the auto sear. This action allows the hammer to be released automatically, striking the firing pin and firing another round as long as the trigger is held down and ammunition is available. The interaction between the auto sear, the bolt carrier group, and the trigger assembly is complex, enabling continuous firing.
Full-Auto Bolt Carrier Group (BCG)
The bolt carrier group is the engine of the AR-15. It houses the bolt, which locks into the barrel extension to seal the chamber. The BCG also contains the firing pin and acts as the mechanism that cycles the spent casing out of the chamber and chambers the next round.
A full-auto BCG, or “full auto carrier,” is designed with additional material. This extra material is specifically engineered to interface with the auto sear. It serves as the surface that depresses the auto sear during the cycling process. This allows for the automated hammer release to continue the firing cycle. Semi-automatic BCGs often lack this extra material, preventing them from operating in a full-auto configuration. It is one of the key differentiating components.
Selector Switch
The selector switch, sometimes referred to as the safety selector, is another critical part. The selector’s primary function is to prevent the firearm from firing accidentally. In a semi-automatic AR-15, the selector has two positions: safe and fire. However, the selector on a full-auto AR-15 usually has three positions: safe, semi, and full auto.
The selector switch controls the trigger mechanism to allow the shooter to choose between semi-automatic and full-automatic modes of operation. In the “full auto” setting, the selector allows the auto sear and other relevant components to function freely, initiating the continuous firing process. The “semi-auto” position ensures that the disconnector functions correctly, preventing the hammer from releasing automatically and restricting firing to one round per trigger pull. The “safe” position mechanically blocks the trigger and hammer, preventing the weapon from firing altogether.
Other Potential Parts
Beyond the core components discussed, additional parts may contribute to the function of a full-auto AR-15. These variations are often related to the trigger group and the hammer. The trigger group is crucial for managing the firing sequence, and its specific configuration is a factor. Furthermore, the hammer design must be compatible with the rest of the full-auto mechanism.
Legal Considerations (Crucial)
Federal Laws
At the federal level, the National Firearms Act (NFA) of regulates the ownership and transfer of full-auto firearms. The NFA mandates stringent requirements for registering these weapons, which includes submitting an application to the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), undergoing background checks, and paying a significant tax. It is incredibly rare for private citizens to legally acquire new full-auto firearms. This is due to the legal restrictions placed on manufacturing such firearms. This makes purchasing an existing firearm the only path. The purchase is subject to extensive background checks and approval from the ATF. Only firearms manufactured before may be transferred to private citizens under this legal framework, which keeps availability extremely limited and demand high. This causes the cost of legally purchased full-auto firearms to soar. The penalties for violating the NFA include substantial prison sentences and hefty fines.
State and Local Laws
The laws concerning firearms vary wildly across the United States. Some states may have stricter regulations than others. Some local municipalities may have even stricter laws, including outright bans on specific types of firearms or components. Before considering anything related to full-auto parts, research and understand the local laws where you reside.
Penalties for Illegal Possession
The legal consequences of owning or possessing full-auto AR-15 parts illegally are extremely severe. Conviction can result in a lengthy prison sentence, often measured in years, and substantial financial penalties. A federal felony conviction can also lead to a loss of other civil rights, such as the right to vote or own other firearms. The consequences are far reaching.
Risks and Considerations
Safety Concerns
Full-auto firearms, because of their rapid firing rate, can pose heightened safety risks. Accidental discharges are more likely, and maintaining control of the weapon requires significant training and experience. The recoil and muzzle climb can be challenging, especially for less experienced shooters. Controlling a full-auto firearm requires discipline and dedication to safe gun handling practices.
Practical Limitations
Beyond the legal complexities and safety concerns, practical considerations exist. The cost of legally acquiring and maintaining a full-auto firearm is substantially high. A full-auto firearm demands a consistent supply of ammunition. The rapid rate of fire consumes ammunition at an alarming rate. In addition to the firearm, the shooter should also invest in extensive training to safely utilize their investment.
Alternatives and Options
Semi-Automatic AR-15s
The semi-automatic AR-15 is the standard in the market and offers significant advantages for the vast majority of gun owners. They are easy to obtain, widely available, and subject to less stringent legal requirements. They offer a great deal of versatility, including self defense, hunting, and target shooting. Semi-automatic versions are also much less expensive to operate and maintain.
Conclusion
Full-auto AR-15 parts represent a fascinating and complex facet of the firearms world. Understanding how these components work, the legal landscape, and the associated risks is vital. The path to owning a full-auto firearm is heavily regulated and demanding, and the penalties for non-compliance are severe. This article provides information on the intricacies of AR-15 full-auto components, providing an overview of how they work and the legal implications. However, this information is not a substitute for legal advice. The complexity of the situation makes it essential that anyone interested in full-auto AR-15 components consult with legal professionals and qualified firearms experts.
Disclaimer
This article is for informational purposes only and should not be considered legal advice. The author is not a legal professional. The laws governing firearms are subject to change and vary by jurisdiction. Always consult with a qualified attorney or legal expert to ensure compliance with all applicable laws and regulations. The information provided is accurate as of the date of this article; however, laws and regulations are subject to change.
Remember: if you are even considering acquiring or modifying an AR-15 with full-auto parts, immediately seek expert legal counsel before taking any action.
