9mm vs 45 ACP: A Comprehensive Analysis of Their Performance and Capabilities

When discussing handgun ammunition, one frequent comparison is between 9mm rounds and 45 ACP. Often, the argument revolves around whether modern 9mm rounds perform similarly to 45 ACP, particularly regarding jacketed hollow point (JHP) and ball rounds. This article aims to provide a detailed analysis, addressing this issue while delving into the differences and capabilities of both calibers.

The Evolution of Handgun Ammunition

Modern 9mm ammunition has advanced significantly, keeping pace with 45 ACP and other calibers. When people compare the performance of 9mm and 45 ACP, they often refer to the effectiveness of JHP rounds in 9mm being comparable to the full metal jacket (FMJ) rounds in 45 ACP. However, this comparison does not hold true for all types of ammunition.

Capacity and Reliability

The capacity of modern 9mm platforms, such as the Glock 30, is often cited as being comparable to 45 ACP platforms. For instance, the Glock 30 holds 10 rounds, which is similar to the capacity of common 45 ACP pistols. The author, who is a former police officer, carried a Glock 21 in 9mm and a Beretta 92 in .40 SW on duty. The author found the 45 ACP to be more accurate due to its smoother recoil, which is less harsh compared to the .40 SW.

Effectiveness in Stopping Power

One of the common misconceptions is that pistol calibers do not generate enough speed to cause hydrostatic shock, a phenomenon debated in the firearms community. Although the existence and significance of hydrostatic shock are still debated, it is important to note that the primary mechanism of injury is crushing of tissue. Therefore, the larger the bullet diameter, the more tissue it can crush.

There have been significant advancements in modern ammunition, which have completely overcome any limitations in penetration. Comprehensive ballistic studies show that 45 ACP rounds have no issues with penetration. There are numerous studies demonstrating that 45 ACP can effectively penetrate bone, thanks to its larger 230 grain projectile. This characteristic allows the 45 ACP to crush and push its way through bone more effectively than high-speed, lighter bullets like 9mm.

Real-World Applications

The large-bore pistol calibers, such as the 45 ACP, are inherently more effective because they create larger wound channels and have a higher probability of striking vital areas. The FBI's own studies support this, concluding that to achieve greater effectiveness in a pistol cartridge, the solution lies in creating a larger wound channel through a larger bullet. Once the round reaches vital areas, speed becomes less critical, and the effectiveness of the wounding channel is the primary factor.

To illustrate the importance of bullet diameter, the Federal HST 230 grain round expanded to an average diameter of 0.85 inches, which is nearly as large as a 12 gauge shotgun slug at 0.88 inches. The surface area of the expanded 45 ACP round is 42% greater than the largest 9mm expanded surface area, Federal HST Micro, providing a significant advantage in wounding effectiveness.

Historical and Contemporary Evidence

Historical evidence, such as the 1920s photographs of 45 ACP rounds hitting cars during prohibition or the heavy steel car driven by Bonnie and Clyde, demonstrates the impressive penetration capabilities of the 45 ACP. Furthermore, the 45 ACP has been effective in recent years in hunting, specifically in killing several grizzly bears. This challenges the claim that 45 ACP rounds cannot penetrate effectively in different mediums.

However, it is important to note that while 9mm rounds are also effective, they rely heavily on expansion to achieve their full potential. A properly expanding 9mm round can reach diameters comparable to 45 ACP, but a larger bore like the 45 ACP provides an even greater advantage in terms of wounding and penetration.

Conclusion

While modern 9mm ammunition has indeed advanced and can perform similarly to 45 ACP in terms of expansion, the 45 ACP still offers a significant advantage in terms of effective diameter and wounding channel. This advantage is due to the larger bullet diameter, which allows for more tissue crushing and penetration. Whether it is due to capacity, accuracy, stopping power, or real-world applications, the 45 ACP remains a formidable option for many users.