No, it is not. The only particularly thick bone is at the top rear of the head and that is because of muscle attachment to help keep the head elevated. Otherwise, the brain is surrounded by two thin layers of bone, usually no more than about 1/8" thick each, but gapped quite a bit by cavities, primarily marrow/sinus-related.
Preacher buddy hunts with a 38 spcl and for years took his shots at the head and put them down easily. Then about 4 years ago a buddy gives him his .357 to use for a sure kill shot and the first hog he saw was a sow facing him. 3 shots, and still standing till the last one knocked her out. He still had to kill her. The first 3 shots on the forehead left a short gray streak where the bullet just slid off. He said he never would have taken that shot had he been shooting his 38 but he was sold on the power of that magnum. He is back to a 38 the last I heard. I use my 32 Win spcl and shoot for the spot just below the shoulder, They don't run and they don't get up. Only thing I shoot in the head is squirrels and rabbits.
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