AR-9 vs AR-15: Understanding Recoil Differences

Welcome to our discussion about the recoil differences between AR-9 and AR-15 rifles. This article aims to clarify the misconceptions around these two firearms and provide a detailed comparison based on their operational principles and design features. Whether you're an enthusiast, a shooter, or simply curious about the performance of these popular AR platforms, read on to learn more.

Overview of AR-9 and AR-15

First, it's important to distinguish between the original AR-9, which is typically a 12-gauge shotgun, and the AR-9 rifles that are adapted for 9x19mm ammunition. The AR-15 is a versatile platform available in various calibers, including 5.56x45mm NATO. The design features of these rifles, particularly the method used to extract and cycle the cartridge, play a significant role in determining their recoil characteristics.

Recoil Differences and Mechanisms

When comparing the AR-9 to the AR-15, it's clear that the AR-9 generates significantly more recoil. This is due to the straight blowback system, which requires a larger amount of energy to operate. The straight blowback system confines the bolt to the rear of the firearm, causing it to slam back forcefully against the buffer tube. Contrarily, the AR-15 with its Direct Impingement (DI) gas system utilizes gas pressure to unlock and retract the bolt, resulting in minimal to no recoil.

AR-9: Straight Blowback System

The AR-9's straight blowback system was designed to be simple and robust, making it ideal for shotguns. However, this simplicity translates to a noticeable increase in recoil when chambered with 9x19mm cartridges. The bolt of the AR-9 is approximately three times heavier than that of an AR-15 in 5.56x45mm. This heavy bolt and its carrier generate a significant backward force, contributing to the higher recoil experienced with the AR-9 platform.

AR-15: Direct Impingement System

The AR-15, on the other hand, employs a Direct Impingement system, which distributes gas pressure through a gas block and into the bolt carrier. This method reduces the recoil impulse by distributing the energy more evenly and allowing the bolt carrier to move more smoothly within the buffer tube. The lighter bolt carrier in the AR-15 also contributes to a more manageable recoil experience.

Recoil Comparison and Caliber Variations

When comparing the AR-9 and AR-15, it's crucial to consider the calibers in which they are chambered. While most 9mm AR variations follow the straight blowback design, modern AR-15 platforms in rifle calibers often use gas-operated systems that reduce recoil. For example, an AR-15 in 5.56x45mm NATO benefits from the Direct Impingement system, which significantly mitigates the recoil impulse.

Recoil Absorption and Buffer Weight

The buffer weights of AR-15s also play a significant role in managing recoil. Standard AR-15 buffer weights range from 3.0 to 5.4 ounces, while dedicated 9mm buffers typically weigh between 5.4 and over 10 ounces. This additional mass in 9mm buffers is designed to handle the increased recoil, but it also means that properly built AR9s have a similar level of recoil to standard AR-15s in 5.56x45mm with a 16-inch barrel and carbine-length gas system.

Recoil Impulse and Performance

In terms of recoil impulse, there are subtle differences between direct blowback systems and delayed blowback systems. The direct blowback system used in most 9mm ARs generates a more immediate and pronounced recoil impulse, which can impact both performance and shooter comfort. In contrast, the delayed blowback system used in some AR-15s in rifle calibers, like the 5.56x45mm M16, results in a smoother and less jarring recoil impulse. This difference in recoil impulse is particularly notable during high-volume shooting sessions or in rapid-fire scenarios.

Conclusion

In summary, while the AR-9 generally generates more recoil due to its straight blowback system and heavier bolt carrier, the AR-15 offers various configurations to reduce recoil, including gas-operated systems and proper buffer weights. Properly built AR9s with optimized buffer weights and configurations can have similar recoil levels to standard AR-15s in 5.56x45mm. When choosing between these platforms, consider not only the specific caliber but also the desired level of recoil control for your intended use.

Key Points:

AR-9: More recoil due to straight blowback system and heavier bolt carrier. AR-15: Less recoil through DI gas system and gas-operated systems. Caliber choice significantly affects recoil, with 5.56x45mm offering the least. Properly built AR9s can have similar recoil as standard AR-15s with well-suited buffer weights.