Jack-in-the-box effect

If an anti-tank projectile or shaped-charge blast manages to penetrate a turreted armored vehicle's hull and subsequently its ammunition storage area, the shock wave or heat and pressure can be sufficient to cause cooking off or sympathetic detonation of the tank's unfired explosive shells and propellant.

[6] The latest variant of the T-90M has been designed with some of the spare ammo in an external storage, which reduces the likelihood, but does not completely eliminate the risk of a "turret toss".

[7] Many modern Western tanks (for instance, the M1 Abrams, Leopard 2, and Leclerc) feature ammunition compartments designed to fail safely under fire, reducing damage to the level of a firepower kill.

Training doctrine mandates that the ammunition compartment door must be closed before loading the main gun, exposing the crew to only one shell at a time.

The larger turret on the western tanks contributes to that additional weight, which has implications for manufacturing costs, ease of transportation, fuel consumption and mobility.

[8] In the Turkish intervention in Syria, images and videos depicting several completely destroyed Leopard 2A4's, some with their turrets blown off, were published in January 2017.