These guys are also making bismuth ammo. (see link below) They are getting low on stock tho. A while back I ordered a couple boxes of 16 gauge bismuth 4's from them. They only had one box left, so they sent me that box and a complimentary box of 16 gauge bismuth 6's. Hard not to appreciate that! Their velocities were a little lower in 16 gauge than the Boss loads.

I see they are completely out of the 16 gauge ammo now, and the 12 gauge offerings are low, but they are someone to keep an eye on.

https://www.backridgeammunition.com