You may get better patterns with buffered copper coated and buffered nickel coated lead shot over just plain lead shot with no buffer.
Copper coated lead or Nickel coated lead maybe a little harder than plain lead. But it is not very hard so it loses some of its shape when the shell is fired and it deforms and flattens out when it hits skin, meat and bones.
There is different types of shot in the above picture that I removed from catalogs when I was doing some penetration tests with different shot.
Top row- copper coated lead number 4 buckshot. They got all smashed up and flattened out when they hit the catalog.
2nd row- Hevi-Shot T shot that is denser than lead and much harder than lead.
3rd row- the 4 BB shot on the left are Remington Wingmaster HD
BBs. The two on the right are copper coated lead BBs and they got smashed up and flattened out when they hit the catalog.
4th row- are Remington Wingmaster HD #2 shot.
5th row- Hevi-Shot B shot.
Coated lead shot doesn't come close to penetrating as deep or breaking bones as good as the harder and denser tungsten alloy shot. Deep penetration is what you want with shotgun pellets.
If you reload shotgun shells you can buy HW13 BB shot and T shot from Bucks Run Sports Supply 1-507-356-2195. You can reload 3" 1-1/2 oz HW13 BB or T shot loads for about half of what Hevi-Shot 1-1/2 oz loads are selling for now.