Good info here Dan. I've used AA3100 in the 45-70 and it bulks up really well and was accurate in every bullet weight and rifle I used it in, but it left lots of unburned powder behind......to the point that it would somtimes be impossible to load the next round in my Shiloh. I tried various crimping and compressing combinations but nothing worked. Actually every AA powder I've tried so far leaves behind a good bit of powder but 3100 was the worst. Did you have this same experience?