Okay, I put my money where my mouth was and gave em a tumble in my little 3# Lortone tumbler for an hour. And I stand corrected.... these little balls do NOT smash themselves flat like the bigger .540 balls that I'm used to. They do smooth out a lot, but they
don't get store-bought ball smooth. They just aren't heavy enough to bang out the high spots.
I still just shoot mine with the sprue up as cast, but if you wanted em to be smoother, you could
probably tumble them in
with some heavier balls, say .580-.620 and get the results you want. But just to put a pile of .440s in a tumbler, I don't know if they'd do better if they tumbled
longer, but here's an hour's worth.
First pic...
As cast:
http://i613.photobucket.com/albums/t...psxlp5u8zf.jpg
And second pic, as tumbled:
http://i613.photobucket.com/albums/t...psc2kc7eou.jpg