J'aime la question. J'ai fait quelques recherches sur l'internet.
Il semble qu'une poudre lente produit moins de chaleur que la rapide.
Pour avoir lu et approfondi sur les calibres 6mm tels que le 243AI exemple. Accuracy recommande les poudres lentes pour une plus longue durée de vie du canon.
The .243 Win excels with a wide variety of powders, and excellent factory-loaded hunting ammunition is available. Off-the-shelf .243 rifles from Howa, Remington, Savage, and Tikka perform admirably with little or no modification. The “improved” version of the cartridge, the .243 Ackley, can do everything its parent can do, with more velocity, and greater brass stability thanks to its 40° shoulder. Among the Ackley variants, the .243 AI is rightly one of the most popular. It is easy to fire-form, and commercial dies are readily available. Barrel life is the downside of both the .243 AI and standard .243. These chamberings pump a lot of powder through a small bore. The result, typically, is rather short barrel life, sometimes less than 1500 rounds. A few folks have been experimenting with the use of very slow, cooler-burning powders. There is some evidence that the use of super-slow powders, combined with modified cleaning regimens, can result in significantly enhanced barrel life.
Je dirais d'utiliser une poudre lente pour baisser la chaleur et permettre ainsi que garder ton canon opérationnel plus longtemps.