Are you sure he said 15 grains???

I'd buy 3-5 grains, if the shooter was shooting open sights in a flintlock...

I am a tapper, I fill the measure, tap down and top it off...I can shoot 2 1/2 - 3 inch groups to 150 yards...

You will see more inconsistances in how you clean the barrel than in weighing each charge, as long as you are within 2-3 grains, with a scoped inline, I'd bet you couldn't measure the distance....

That being said, if you feel better, measure each charge...It won't hurt a thing...This is a hobby!!!