So what comes first? If trying to develope a load and your limited to mag length do you first start with different grains of powder, find the most accurate regardless of group and start adjusting the seating depth or do you switch powders to try and find a more accurate powder. If you know the seating depth of an accurate load i.e. factory load should you duplicate that depth, find an equally accurate powder combo then slowly extend seating depth. It just seems with all the different factors you could shoot your barrel out before finding an accurate load.