I have a 300 win mag that I want to use to hunt deer. Not big ones either. Like Blacktail. Just don't have the Ca$h or time this year to get a new rifle. So I want to try some light loads for my 300 mag. Like getting it to shoot slower, like a 30-06 or 308. Every reloading book I have does not have a glaringly obvious write up about how to do this. Do I simply just use less powder? Where do I start researching this info?