Hmm, what kind of ammo do you use.
Plus, the cloth is spreading it out over a loose, very wide surface, while the bones in the skull would absorb the direct blunt of it a lot worse.
I've broken through half inch of glass, wood, plastic, killed various animals, busted up fruit.
And I know that many primitive tribes hunt larger animals (wild cats, wild dogs, etc.) with them.
I mean, I don't want anyone to try to get the idea that this would be a good weapon... but hey, if its all you got.