Tired of always hearing that swaged bullets were almost pure lead, I decided to contact the bullet companies I know that made swaged lead bullets.
Note: all my casting was with 10-13 BHN for everything, including hot .44 Rem Mag. When I started shooting rifles at over 1800 fps, I just used a gas check and didn’t change alloy.

Magnus uses 97/3 alloy, for BHN 11.

Precision Bullets uses 92/6/2 and reports the bore-riding surfaces are 13-14 BHN. They also restrike after the coating process.

Hornady reports 95/5, for 13 BHN.

Zero uses 97/3, also, for BHN of 11

Speer reports it is proprietary, and they “have a max velocity of 1100 fps.”