It is my understanding that a 'detonation' occurs very rarely if and when a cartridge case isn't near to fully filled with a slow burning powder such as 4831. Some reloading folk will warn the beginner not to use those slow burning powders for 'reduced' loads. I have never been close to such a thing, but it is still spoken of in the magazines. Magazine writers recommend one use 'fast' burning powders for reduced loads, not powders considered 'slow' that are used for magnum cartridges, to avoid 'detonation'.