I am attempting to build a sub-sonic load for a 45/70. I have decided to use the RCBS 500 grain boolit in one of my Marlins. Weighs 521 gr. out of my alloy, I have tried 2 powders so far. Worked up to 14 gr Unique, and up to 24 gr of 5744. The 5744 seems to have the accuracy edge throughout the charge range,21-24 gr, but the Unique load, from 12 to 14gr. is by far the quieter. I am looking for the quietest load I can find that will run just below the sonic level. Needs to deliver "hog" accuracy from 50-70 yards. So far the Unique loads are delivering "OK" accuracy of about 2 inches at 50 and the 5744 loads are delivering about 1.5 inch at the same distance. Has anyone else experimented in this area? and if you did, what powders, or combinations did you use?