Could a Naval 5-Inch Gun Defeat the Armor on an M1 Abrams Tank?

**Introduction**

The debate around the effectiveness of a naval 5-inch gun against an M1 Abrams tank has been a topic of interest among military strategists, historians, and enthusiasts. The 5-inch gun, with its approximate calibre of 127mm, is notably larger and more powerful than the 120mm used in the M1 Abrams tank. This article delves into the capabilities of such a naval gun and its potential impact on tank armor.

Capacities of the 5-Inch Gun

Compared to the 120mm main gun on the M1 Abrams, a 5-inch gun has a larger bore, providing greater destructive power. Additionally, it has propellant loaded to a higher degree, enhancing its overall performance. A significant advantage of the larger calibre is the increased volume of explosive per shell, which can cause extensive damage to armor and the crew inside the tank.

Impact on Armor

A direct hit by a heavy artillery-calibre High Explosive (HE) shell can cause severe issues for an M1 Abrams tank. While penetration of the main armor array is unlikely, the separation between the bursting plate and the interior armor layers can mitigate some of the impact. However, the blast from a high-order detonation and the shock wave from the impact are sufficient to render the tank inoperable. Delays in mission tempo and even total mission kill are likely scenarios.

Critical System Disruptions

The explosion and subsequent shockwaves can cause multiple issues, including:

Immobilization of Running Gear: Damage to the transmission, tracks, and drive system will prevent the tank from moving. Engine and Fuel System Damage: Shock to the engine, fuel lines, and cooling systems can lead to immobilization and fires. Hydraulic, Electrical, and Electronic Malfunctions: Shock damage to the hydraulic, electrical, and electronic systems can affect the tank's operational capabilities, degrading or eliminating its ability to fight effectively. Direct Injuries to Crew: Shock and shrapnel can cause injuries, potentially incapacitating or killing crew members. External Fragments: Splinters from the shell and secondary fragments from the terrain can perforate external fittings, weapons sights, and optics, disabling the tank even without penetrating the main armor. Roof Hits: Hits to the roof can penetrate the armor even before the explosion takes place, causing severe damage. Turret Displacement: The momentum of a large shell is enough to dismount the turret, either completely or to the point where it can no longer function properly.

Historical Evidence

Historical testing, particularly from the 1980s, demonstrated that field artillery could be highly effective against tanks. The U.S. Army, for instance, tested this in the 1980s and found that the casualties between exposed infantry and armored vehicles, including tanks, were similar. While the tanks were mostly disabled and could be recovered and repaired, they were effectively 'lost' in the context of a defense in depth by mobile forces against a numerically superior attacking force. This would result in positions or those they supported being overrun or bypassed in the confusion of the battle.

**Conclusion**

The effectiveness of a naval 5-inch gun against an M1 Abrams tank is significant, given its high-calibre and powerful explosive content. While the main armor array is unlikely to be penetrated, the shockwave and explosive impact can cause mission-crippling damage to the tank's critical systems and its crew. Historical evidence supports this, showing that field artillery and similar calibre weapons can be highly effective in disabling tanks even in complex battlefield scenarios.