Lead wheel weights got banned a while back in CA, but you can still find lots of them along the freeway, or get them from tire shops still removing the old ones.
If you use them in BP revolvers, they are kind of a tight load because the alloy is a little harder, benefit is they seem to group tighter, drawback is they make them even more involved to clean ‘cause they foul a bit more...
I use them in my pair of 1858 New Army .44’s all the time.
I got lucky, a friend works at a car dealer. :>)
Back when I was getting ready for SASS matches I acquired a pair of Pietta 1858 New Army .44’s with sequential serial numbers. Serious health issues made me drop the idea of matches though. Really like the Piettas even though the hand and bolt springs broke. Flat bolts were replaced with home made wire springs and hand springs from VTI. R&D conversion cylinders for .45 LC worked real well with BP cartridge loads, to go with the Rossi 1892 SRC (no lock).
Smoke, fire, and the smell of brimstone.