RE: Loose vs pellets
Pellets are convinient, consistant in size (each 50 grain pellet is 50 grains), and expensive.
Loose is infinately adjustable for weight, fits any bore size, and iseasily measured by volume.
A lot of arguments could be made for the advantages/disadvantages of both forms. Personally, I use loose. With a couple "speed loaders" in my hunting pouch I can reload at about the same speed with either form of powder and the loose allows me to easily vary loads when testing for performance & accuracy. I can use the same powder for my sidelock and inline with loose, and I can also use it in my pistol or shotgun.