Zombie Apocalypse: Crossbow question?

with a sharpened arrowhead (as opposed to blunt) it could take as little as 6–8 psi to penetrate the frontal bone. I don’t know about the sides or the back.

Unless their mouths are open and you shoot it directly into the mouth and penetrate the brain stem from through the back of the mouth

Over 9000 Pascal
You will not need more than you would need for a standard issue human.
I know this, because I tested it on many humans and zombies of various sizes.

A Diamond Bowtech Liberty compound bow set at 60 pound draw with 80% let off, will fire a carbon fiber arrow with a 100 grain broad-head, at a speed of 300 fps. That will go right through a full size deer if hit in the ribcage and will pass through the shoulder blade but not make it out the other side.
Is a deer shoulder blade stronger than a skull? If yes, you have your answer.

If the projectile has a very narrow, sharp point, just about any poundage should be able to penetrate bone with a crossbow. Crossbows are basically all high poundage, so a pistol crossbow between 60–80 pound pull should be fine. Mine is an 80 pound, and I’ve punctured material harder than bone with it. The weight of your projectile matters too, of course, so a full sized crossbow has that advantage, and the material that the point is made from will influence how the force is applied. For puncturing, you want something that doesn’t deform much.

One thing to remember: human (and therefore zombie) skulls are harder in the front and back than they are on the sides.

Thank you all for answering and bringing such great news. I respect and value your opinions and I think I’m going to get one.

Can anyone recommend a good one? Or some good bolts? :D

Check the rules for your state. There may be restrictions about where and when you can use it. If you are using the “real” hunting bows and crossbows you must be more than 500 ft from a residence and a similar distance (maybe 800 ft? from the road.)
Know what you are doing. Follow the same rules you would if you were using a shotgun with slugs. Know your backstop. The high powered bows will pass through an amazing amount of material. A deer slug will open up and stop when it hits something. A carbon fiber arrow will penetrate and just keep on going. Never dry fire it. There is so much potential energy stored in the retracted arms they can be damaged if you dry fire it even once.
In NY, you need a special license to hunt with one. Take the hunter safety course if you are a beginner. Even if you don’t hunt, you will learn a lot.

Remember, it only takes one mistake with one of those babies and you won’t have to worry about zombies ever again.

”The hunter safety course” and that is…?

And yes, I will put the utmost care into the preservation and handling of this tool, as it is a weapon. I will only use it for target practice (unless the zombie apocalypse actually does happen) and even then I will be extremely careful as I know any/all weapons deserve respect. If it can take a zombie out, it can take me out too.

Your state Department of Environmental Conservation, or similar organization, will offer a Bow hunter Safety Course. I forget how many hours it is 12? 16? At the end, you have to demonstrate proficiency with a bow set at the required poundage necessary to provide a clean kill at 15 yards. You have to hit a 6 or 9 inch pie plate. I could easily drill a 2 inch hole every time – at 50% above the minimum draw. (I practiced a lot.)