Sproulman, that 70 grain load should be giving you something like 1450 fps. If you sight it for a 75 yard zero it will be about 1.5" high at 25 yards, 2" high at 50 yards, dead on at 75 yards, and 4.5" low at 100 yards.

Those burn throughs with 70 grains are likely due to either the patch being a little too dry or the weave of the patch being a bit loose. What patch material are you using? You should not need a bore button with a patched ball over 70 grains of 3F GOEX.

How did the accuracy compare using 70 grains with the bore button and without the bore button?