I'm going to start loading this cal for the first time and will be using the RCBS 200gr GC. What's the best place to start, powderwise? I have the Lyman handbook, which list loads only for the faster powders. I have a lot of SR-4756 and Unique, but I was also wondering about slower powders like IMR4198 for accuracy. Will be shooting with a Remington M14 and a 336 micro-groove.