I started reloading for doubles using those articles plus some from Ray Marriage and others. Everyone was using 3031 because the burn rate was similar to cordite and a 1 for 1 substitute was a starting point. It was hugely frustrating because a minor change in powder weight would throw your groups all over the target and to change from one lot to the next ment burning a lot of powder to get regulated again unless you were lucky. Thank goodness for modern powders and the guys that taught us how to use them!