I have a .40 cal GM barrel for my TC Hawkin, and it is considerably more accurate with 2F then 3F, my daughter and I tried .390,.395,.400 balls several different patches, different brands of 3F,GEOX,Swiss,last of my Elephant several different charges, I'd pretty much given up on getting squirrel head accuracy, we was out in back yard shooting she was shooting TC .40 and I was shooting a .50 cal using 2F,she ran out of 3F so we used the same powder measure she had been using and just used 2F be durned if her next half dozen shots wasn't in roughly inch group at around 30 yards best we'd done with it before was at least 2.5" at same distance.