The Evolution of Submachine Guns: Why Early WW2 Submachine Guns Were Restricted to Pistol Ammunition

In the early years of World War II, submachine guns were primarily equipped with pistol ammunition due to the inherent challenges of rapid fire with full rifle rounds. This article delves into the technical and tactical reasons behind this decision, highlighting the limitations and advantages of submachine guns during the era.

Technical Limitations of Full Rifle Rounds

The recoil generated by full rifle rounds makes them difficult to control when fired in rapid succession from light weapons. Full rifle cartridges are both long and heavy, requiring longer barrels to effectively control the firing process. This characteristic is compounded when aiming for close-quarters combat, a scenario in which submachine guns excelled.

The Role of Submachine Guns vs. Light Machine Guns

Submachine guns are smaller, lighter, and more portable versions of lighter machine guns. The term "sub" in submachine guns signifies that they are smaller and more compact versions, designed for close-quarters combat.

Some countries, such as Germany and Italy, initially developed submachine guns using pistol cartridges. Full power rifle cartridges were deemed too cumbersome and difficult to control in fully automatic mode. This is in stark contrast to heavy machine guns like the Browning Vickers and Maxim, which were designed for long-range, sustained fire situations.

Origin and Purpose of Submachine Guns

The primary purpose of submachine guns was to provide a highly portable and versatile weapon for use in trench raids and close-quarters combat during World War I. These weapons were designed to be carried by raiding parties who needed to deploy quickly and engage targets at short ranges, often with minimal ammunition available.

The British Sten gun and the American Thompson submachine gun (tactical SMG Trench gun) were among the notable models that saw extensive use. The German MP40, for instance, was a well-known machine pistol that was designed to be both effective and highly portable.

Early Examples and Variations

Germany and Italy were among the first to develop submachine guns using pistol calibers. The Italian Beretta Model 1915 and the German MP18 were early examples of these weapons. While some nations, such as the Soviet Union, produced the PPSH-41, which firing the 7.62x25mm T cartridge, others, like Germany with the MP18, opted for the 9mm Luger round, highlighting the variations in design and effectiveness.

Other notable examples include the Greek Reising SMG, chambered in.45 ACP, and the American Thompson M1928A1, known for its powerful.45 ACP round. These weapons demonstrated the advantages of using pistol ammunition for rapid fire in close-quarters engagements.

Transition to Modern Assault Rifles

As World War I progressed, and through the interwar period, submachine guns continued to evolve. By the time of World War II, many countries had developed a wide range of submachine guns using various pistol calibers. These weapons were manufactured in large quantities due to their relative simplicity and cost-effectiveness compared to full-power rifles.

However, the advent of assault rifles in the mid-20th century marked a significant shift in infantry weaponry. Assault rifles, such as the Soviet AK-47, represented a blend of the strength of full-power rifle rounds with the compactness and ease of use of submachine guns. They fired intermediate cartridges that provided a good balance between lethality and controllability.

Today, while submachine guns are still produced for specific military and law enforcement applications, their primary role has largely been replaced by assault rifles. Some modern submachine guns are shortened versions of assault rifles and can be classified as such, but they are not true submachine guns in the traditional sense.

Modern Applications of Submachine Guns

Modern submachine guns are primarily used in close-quarters combat situations, such as urban warfare, SWAT operations, or special forces missions. While less common in mainstream military use, they continue to serve specific roles where their compact nature and ease of use remain advantageous.

Examples of modern submachine guns include the FN P90, created for CQB scenarios, and the East German HK MP5, which retains its original design but has seen significant refinements over the decades.

In summary, the early submachine guns of World War II were restricted to pistol ammunition due to the inherent recoil and technical limitations of full rifle rounds in compact weapons. The evolution of rifle technology and the introduction of assault rifles have since rendered submachine guns less reliant on pistol ammunition, with their role primarily relegated to specialized applications in modern combat.