Here's my evaluation of Because I am cheap, I bought their "dirty" shot which they do not recommend for reloading. They also sell clean reclaimed shot, but it costs more.
One bag weighed 23 pounds, another weighed 19 pounds. I did not weigh the other bag.
I did not bother washing the 1st bag of shot that I smelted (the one that I didn't bother to weigh) because I assumed the dirt would be skimmed off in the smelting process. In hindsight that wasn't quite true. The shot appears to be encapsulated in hard clay, effectively forming an "eggshell" around the lead. Even if you heat the shot enough to melt the inner lead, it has a difficult time escaping the shell. I ended up skimming off a lot of shot along with the dirt, so next time I will try washing the shot first.
The first bag of dirty shot yielded 17 pounds and 10 ounces of clean ingots. The yield probably would have been higher if I had washed the shot before smelting.
I have no fancy equipment to determine the chemical composition of the shot -- which Rotometals says is about 3% - 5% antimony -- so I can only test density and hardness.
Density and some other alloys for comparison:
Reclaimed shot -- 2719 grains per cubic inch
Clip-on WW -- 2794
WW + 2% tin -- 2780
Lyman #2 -- 2703
5% tin -- 2776
I was surprised at the density being closer to Lyman #2 than to wheelweight. Either this shot has 9% antimony or else there is some bismuth mixed in with it -- I find it easier to believe the latter, because you would not expect lead shot to have 9% antimony, but you would expect to find some bismuth shot at a shotgun range.
Bismuth is soft and brittle so pure bismuth would make a poor bullet. But I have no data on how bismuth affects a lead-antimony alloy.
Since I always heat treat my wheelweight, I heat treated some sample bullets at 480 degrees F in the shop oven.
Air-Cooled: 15 BHN
After one day: 38 - 42 BHN
After one week: 41 BHN
after one month: 46 BHN
after 5 1/2 months: 37 BHN it's going down
after 20 months: 29.5 BHN