Andreas-

Never trust the thrown charges from a powder measure.
Never never never when loading for a double rifle.
Otherwise you're just as well off pissing on your leg.

If you are loading for a double rifle and feel the need to use thrown charges from a powder measure, throw them light, then trickle them up to weight in a freshly leveled high quality beam scale.
Keep the charges within 1/10th grain.
If you are using filler, weigh each charge of filler too.

In this case where you are setting up a rifle for a regulation load, also weigh and segregate your bullets

--Tinker