What must be done to modern smokeless powder to enable it to burn with explosive force?

To burn with explosive force, modern smokeless powder requires confinement within a strong container. When tightly sealed inside a container, like a firearm chamber, the pressure that builds up as the powder ignites allows for a rapid and much more powerful combustion reaction. The confinement increases the efficiency of the burning process, transforming the chemical energy into an explosive force rather than a simple burn.

In contrast, exposing smokeless powder to air or mixing it with water would not achieve the necessary conditions for an explosive reaction. Leaving it exposed diminishes the efficiency of combustion and can lead to uneven burning, while mixing with water would dampen the powder and prevent it from igniting effectively. Storing it in a cardboard box does not provide the required structural integrity to contain the pressure generated during combustion. Thus, the use of a strong container allows the powder to reach the explosive threshold and function as intended.