Nickle Plated Buckshot
Someone mentioned this as "hardening" the pellets. It is only a coating. I pattered different 00 buckshot loads a decade ago. The plated but not buffered S&B shells were not exciting. At the time the best I found was the reduced recoil police Remington eight pellet load, which was buffered and not very hard lead pellets. I believe that reducing velocity reduces pellet deformation and thus improves patterning. I'm talking about no more than 20 yards now which was my specified distance as I was looking at personal protection. I never tried them at LONG distances.