Beam scale is about as accurate as you can get for consistency. The objection to them is that it takes a bit more time.
Why agonize about weights? For years the most accurate shooters, those in benchrest competition, dumped their loads out of powder measures. Unweighed. You'd be hard put to beat them with a sporting rifle.
I believe benchrest shooters tend to gravitate toward powders that meter well unlike some of the ones I use.
