Re: 300 WSM Seating Depth / Coal
I have the same mag length constraint (I think anyone in a SA does) and have been able to get pretty good accuracy with 168 Nosler ABs seated to a COL about 5 thou shorter than mag length. I also shoot 168 Barnes TTSXs in this rig as they tend to prefer being 30 to 70 thou off the lands.
Worth noting I am certainly not a competitive benchrest guy! I get about 0.85 inch average with my best load in either above bullet, and nothing more (Winchester M70)
I have had good luck with IMR 4350 and WIN 760 for powder.