Not many people use Ramshot powders, but True Blue is the best metering powder I have ever used, especially when metering small amounts(it's the only Ramshot powder I have tried so far, but I plan on trying others). I have used most of the powders listed on this page but none compare to it. Not saying that it's better than any other listed, it just meters better. Ramshot has a load listed on their website for your Berry bullet.
Where Unique is a large flaked powder, most of the others mentioned (231, Power Pistol, Tite Group, etc.) are tiny flakes. True Blue powder is actually little tiny spheres. If you spill it, they roll all over the place. In general, the smaller the particle size, the more consistent the metering will be.
True Blue is extremely touchy in 327 Mag loads and I don't like using it there. But I have used it in numerous other cartridges(9mm, 357, 40, 44 Mag) with good results. Haven't tried it with 380 though.