I made a batch of 6% antimony and ~0.3% arsenic:
1 part Superhard
1 part reclaimed shot
7 parts clip-on wheelweight
density = 2730 grains per cubic inch
I had predicted that the density would be 2752, so my mix may be a bit "rich."
Compare that density to other alloys:
Reclaimed shot -- 2719
Clip-on WW -- 2794
WW + 2% tin -- 2780
Lyman #2 -- 2703
5% tin -- 2776
91/6/3 -- 2700
Linotype -- 2597
When I attempted to heat treat some sample bullets at 480F in my shop furnace, about half of the bullets melted partially. That doesn't make sense because in theory the melting temperature of 6% antimony should be the same as for wheelweight.
Update: I put a sample bullet in the center of my shop oven and slowly walked up the temperature in 5 degree increments.
430 to 470 F: no issues
-- 475: surface texture changed from shiny to fuzzy
-- 480: very slight slumping at the base of the bullet.
So 480F is definitely too hot for this alloy. Next time I'll try heat treating this mix at 465F. I have no explanation for why this mix has a lower slump temperature than wheelweight, but I can't argue with the data.