Been using the Super T-Speedloaders(below) for many years. Nice as you can load both the charge & bullet in separate compartments plus they have a volume measurement which helps confirm your measured charge. End caps are rubber composition & very tight keeping moisture out. Great for both inline & flinter as it also has a short starter built-in.
I've been using something similar.....but it doesn't have the measure. Mine are either T\C or CVA. Look sumpin like this below. I find 'em very nice when I need a fast second load. I have the PRB (.54 cal) or a Pa. Conical (.50 cal) in one end and the BP pre-measured load in the other.
I have one of those leather strapped traditional wooden roundball loading blocks I used to hang around my neck but sometimes all that traditional stuff doesn't cut it in the real world....least mine!! lol