Nothing wrong with debate. It is my understand that the cast bullets guys use cartridges with small case capacities to eliminate the need for fillers and give 100% loadiing density. They might be using 12 gr. of 4227 in wide mouth 32-20 case and a 32-40 bullet, or something along those lines. For gosh sakes don't load that, it is and example to make a point, not a real load. At any rate if you are really into this do some research and get a rifle made up for the purpose. A small capacity case and a barrel suited for long bullets might be fun. I have the idea of a highwall in 32 H/R mag., a .308 barrel, 1:10 twist, throated for a Lyman 31141 bullet. Maybe launch them at 1100 fps. I bet a guy could make such a combo shoot really well on a calm day. I think it would be really fun but have to many irons in the fire to get into it.

I disagree, but that's what makes for debates. I looked in The Fouling Shot, house magazine for the Cast Bullet Assc., but while they give a great deal of data on the loads used by the CB benchresters, they don't have a listing for fillers, if a filler is used.
I do have one load that will give 1.5 MOA at 200 yards from a box stock Win. M70 usinf a 1.0 gr. tuft of dacron. Shooting the same loads without the filler and raising the muzzle, groups open up to 2 MOA or larger.
My 300 yard cast bullet load uses a filler as well, but the rifle is an 11 pound gun that would wear you out if you had to raise the muzzle for each shot for a ten round string. That load is a 2.5 MOA load and without filler is 5 MOA. The latter probably because the rifle is awkward to raise from the bench. As most CBA benchrest guns are heavier than mine, I doubt they raise the muzzle and I'd bet they do use a filler. Well, at least some of them anyway.
Paul B.