Depending on diamater solids like that are typically used for very dangerous game. That one looks like it expanded correctly. They are designed to have petals that fold out but not completely mushroom so it cuts a huge bloody channel through the beast. hope is in it dying before it gets close enough to sht stomp whomever shot it. If they expand too much it won't get far enough into the critter.
Ages ago it used to be hardened lead then in the 80s it was tungsten core in a casing of lead with copper jacket. Now the preferred dangerous game bullet is copper solids.
Copper solids have no jacket to shed and will only expand if its designed into the bullet.
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