Thanks for the welcome, Idaholewis.
To my way of thinking, what the Muzzleloading Forum does or doesn't do has nothing to do with my earlier comment. Black powder is a very weak propellant and I don't believe that one grain more or less of it in a load will have a noticeable effect on a shots accuracy for the average traditional or in-line shooter.
It's not as though I only shoot muzzleloaders. I shoot modern centerfire rifles too. I also reload the ammunition for them which is why I do know about making precision cartridge loads .
Ask my Ruger #1 in .223 about shooting the staples off of targets at 100 yards because just shooting for the bulls eye isn't challenging enough.
Yes. The folks who compete at Friendship and other shoots weigh their powder loads using powder scales. They also weigh each individual ball or bullet and many of them won't allow a variation of more than a tenth of a grain.
They are into serious shooting and they are looking for anything that can reduce the size of their groups. To them, even a reduction of 1/16" in a 5 shot group is important.
They also set out wind flags at intervals between the shooting line and the target so they will know which way the wind is blowing and how hard so they can make allowances for it with their aim.