My club did a reclaimation project last summer. I learned two things.
1. A terrific amount of dirt and 'fines' go into the barrels.
2. As lead was going into a drum, the contractor compacted it by pounding the bejeezus out of the sides with an 8 pound sledge.
The first barrels processed were the lightest. The lightest I remember was about 2350. As the contractor got his equipment dialed in, later barrels were significantly heavier. The average for a semi load of 55 gal. drums was just shy of 2600 lbs per.
When we mined a few years back the 55 gal drums were full to the rim. This material had been scraped into rows, and processed through a rotating screen separator. They took these drums and ran the lead through a cleaning process to remove dirt and rocks - they were several inches (maybe 4 or 5 IIRC) below the rim after this process.
Assuming 3% antimony, 55 gallons with no voids would be 5125 lbs. If you fill a volume with spheres - like shot, the absolute highest packing efficiency is 74.05% which would be 3,795 lbs (assuming the spheres are identical in size and stay spherical). Really loosly packed, unvibrated, etc. the packing density can drop as low as about 53%, or 2,683 lbs. Best guess for clean lead, would be from 2800 to 3200 lbs.
Of course a 55 gallon drum isn't necessarily 55 gallons either. I think if your buying you want to assume a number around 2,600 lbs. IF your selling you probably want to talk about 3,200 lbs.
As I work for a reclaimer, our barrels weigh between 2800 and just over 3000 lbs. The difference is not oxidation but more into typical shot size; ie: a barrle of 8's and 9's will weigh a lot more than 7.5's and 8's. Nobody gets heavier or cleaner lead per barrel than we do.
Dick, where are you working? I'm looking to purchase some shot from Silver Dollar in Odessa. I wondered how clean it would be. I purchased some from Robinson Ranch(1500 lbs) and it was very clean but had a lot of flat sides. Jackie B.
Flat sides on shot being a concern to some. That always makes me laugh. Did you folks notices that Winchester just came out with a new hunting load where the pellets were intentionally made with many flat sides? Lots of benefits for an iron shot hunting load and not necessarily impending doom for a target load.