Or just buy lead egg sinkers that already have a hole in them, just make sure they're not the non-lead type.
Tim
This is what I was going to suggest. I had a listing of which size to caliber but haven't found it. If I stumble across it I'll post up the info.
Ah ha I found it.Egg Sinker Size:
Size 10
For use in .270, 7mm, and .30 Calibers
Size 9
For use in .338, .348, 38/.357, and 35 Calibers
Size 8
For use in .41, .44, .45, and .475 Calibers.
As with everything else use good smart safety procedures, like starting with checking to see if gun is loaded..........