I will agree that if you are wanting to perfect your load, loose is definitely the way to go. When you buy pellets they aren't all identical, so obviously each load will be a bit different. Personally, I use pellets when hunting though. I started out using black powder, and went to loose Pyrodex, then loose 777, and now I'm using 777 pellets. I find the pellets to be convenient. My pattern may not be the absolute smallest that it could be, but it is definitely small enough to ensure an ethical shot at the ranges I will be willing to shoot at.
But...
I am awaiting my new Optima Elite, and I plan on trying some Blackhorn in it which is loose. Maybe I should wait to post this until after I've worked up a load of that stuff...

rw