The performance of armor piercing rounds using conventional propellant stables at room temperature(21ºC) and peaks at high temperature (52ºC). The higher atmospheric temperature rises, Chamber pressure and muzzle velocity gets higher and faster. 1/

But too much high pressure over designated peak pressure caused by hot atmosphere can lead gun tube and breach to erode or explode. Safety matters the most.
Also muzzle velocity and chamber pressure of conventional propellant falls severely under low temperature below -20ºC 2/

leading penetrator to perform badly against target. Thus the appearance of solution that coating propellant's surface with temperature-insensitive material:Surface Coated Double Base(SCDB) was highly welcomed worldwide. R&D on it became eagerly activiated. 3/

Even development of Electro-Thermal Chemical gun which could solve same problem fell under its appearance due to its complicated design and expensiveness over SCDB.

This time, I'd like to introduce some propellants used on US, German tank ammunitions on this thread.

4/