is the fact that it expends all its energy in the animal not passing through,,that said any bullit that exits the target is wasteing energy that isnt doing anything
This is a complete falacy and a physics impossibility. The magnum bullet expends far more energy inside the animal. The fact that it still has energy when it exits is purely because it had plenty the spare. The reason your less powerful bullet expends all its energy in the animal and does not exit means it ran out of steam before finishing the job.
but here they just punch holes clean through.
This is also an old wives' tail. The faster the bullet is going, the more rapid the expansion. Period. Unless you use really tough bullets in the faster rifle, but then it's the bullet that is causing the performance difference, not the cartridge.