Danger! Light loads in big cases can blow up.

http://reloadammo.com/liteload.htm

Or here
Is Detonation Real?
There has been a lot of ink spilled about the phenomena called detonation. As I shoot I lot of reduced loads with and without a filler it has long been an interest/concern of mine. From all the info I've been able to gather over the decades the description Howlin' gave is the one most agree on. However, if pushed a little no one I've spoken with or written to has confirmed that 100%. I don't know if that matters because 100% of those I've communicated with and every experienced handloader I know agrees that with very light loads of fast burning powders there is something peculiar that goes on, sometimes with devastating results. As Pawpaw mentioned H-110 and 296 seem to be the greatest offenders if charges are reduced below recommended levels. Other faster burning powders have also been known to create the situation.

I have never, personally had any problems with any reduced load I've used nor have I ever seen an example of what is called detonation other than in pictures. The method of my personal reduced loads are well documented by proof houses and highly experienced handloaders and I don't vary from the formula. However, with certain powders there is no question that occasionally "something peculiar" happens.

As others have mentioned if a loader stays within the guidelines of published data there shouldn't be any problems. For those old or seldom seen cartridges there is powders available to day that pretty much eliminate any guesswork in building a suitable load. Trail Boss was mentioned by db and AA5744 is another.

Good thread, interesting topic.

https://www.thefirearmsforum.com/threads/is-detonation-real.174838/