I know the BP for sporting use is graphite coated, but the FA grades are not graphite coated. Thing is FA grades are not normally sold to the general public, and most places require an ATF license unless you can certify that you are going to use it in bp guns. Ace Pyro sells commercial non graphite coated bp (FA grades) and will sell you 50 lbs if you can certify that you will use it for bp guns and not fireworks. But their minimum order is 50lbs and that's way more than 100 rocketeers will ever use in 20 lifetimes. But also FA grading scale is different than FG grading scale. FG grades are always graphite coated and FA scales are not. If you somehow came across a shop selling FA grade bp then you have to get 7FA because that's equivalent to 4FG. If you get 4FA then it's more like 2FG and as a result you'll have to change the charge amount to compensate.
But most gun shops won't sell FA grade bp because if you use them in a gun, it's going to lead to performance issues (2FA bp for example will not function well in a rifle because it is more like cannon grade bp).