Mike,

IMHO, IMR-4350 doesn't do well with reduced loads. I've always gotten the best accuracy with loads near the top of the book loads or just over book with this powder. But there is a way to load pretty good reduced loads using H-4895. Go to the Hodgdon website and look for the reduced loads for beginners section. It will give you a good deal of info. This is what I did when I was starting Katie with her .243 Win with reduced loads. It worked quite nicely for her.

Slower powders sometimes experience a situation where the reduced load results in a detonation when fired.. Evidently there's not a lot of technical data about what happens, just the knowledge that it does happen.