I have been experimenting with bullet weights myself. The ones I have are too shiney but they were so cheap I couldn't pass them up. The BPS GP painted ones are $4 per 10 and I bought these for $0.50 a bag of 12.
Tried putting a bags worth in a plastic bottle with some Coke to dull them. It worked but not very well and they were in there for about two weeks. On a saltwater forum a guy mentioned using Drano which I may try?
Powder painting is the best option but the hole gets painted shut or the piece of wire that holds the weight fuses to it.
If all else fails I will just spray paint them with a can of OD primer like before. Doesn't hold up the best but some days they do not last long enough to lose their paint.
Allen