My vote at this time is three shotgun blasts. Not necessarily the same load. The top grouping looks like a magnum load, I think Remington makes a 15 pellet "00" load. Middle looks like it could be a 9 pellet load, and the bottom load got split. I see what looks like one pellet that deformed the rim and another 3-5 pellets just inside the orange box. Either that or someone with a .22 was trying to zero a scope and walked their groups in and the shot to the rim was the bullseye.