If you shoot a guy in the head seven times at close range, I don't think it matters what kind of bullet you use.
Didn't some Hollywood soap opera idiot die a few years ago when he shot himself in the head with a revolver loaded with .44 blanks?
That was Jon Eric Hexum. Fooling around with a .44 loaded with blanks. He didn't realize that the wadding they use in blanks is sufficient to penetrate your skull at the temple, where the bone is thinnest. He pretended he was committing suicide by putting the gun to his temple and pulling the trigger. He was the co-star of Cover Up where he was a secret agent undercover as a male model. The show died shortly after he did.