i second the Lee Powder Measures advice
I use them and a playing card and THEN weigh (although for mass production, there is no need to weigh). Inevitably, I am within under 1/2 grain.
Bought a commercially made...
cap for the "Goex" that has a brass spout, its secured to the inside with a nut and lockwasher, uses a rubber cap to close.
to use, replace the original with the spouted cap, and pour into measure (T/C), then put cap on, before firing.
With a "Pyrodex" bottle, am using an aluminum kitchen funnel that fit inside the measure. caap the bottle then shoot.
When shooting winter matches at club, I make up paper cartridges using the "zig-zag" paper, using a 7/16 diameter brass tube from hobby shop, this makes a tube for holding 50 grs of 2F.
Go to match and draw a cartridge, tear then end over muzzle and drop in, seat patched ball and fire. Make cartridges the evening before.