I think that is probably a low estimate. I just figured I shoot about 50 rounds a week of .45ACP alone. 230x50 is 11500 grains divided by 7000 is 1.64 pounds a week x 52 weeks is about 85 pounds of .45. I will also shoot another 50 through an AR or AK, plus various hunting rifles up to a .416, plus vast .22 bullets, then shotshells at 16 shots to a pound. I probably put 600 pounds out myself. I do my part though, and shoot some Barnes bullets (all copper) on a lot of big game. The whole idea is BS anyway.
How many times have you seen a sparrow eat a spent .45ACP or a 45/70 Govt.?
Bird shot from skeet, trap or sporting clay ranges is reclaimed and sold as recycled shot for reloading.
I am sure the same is done on rifle ranges if it can be dug up.
These wacko groups and the EPA do play fast and loose with the unsubstantiated numbers they pull of out the blue.