That’s a good question, can a bulletproof vest stop an arrow? The guys at Bullet Safe decided to put it to the test. They shot one of their high-end bulletproof vests with both a compound bow and a crossbow with arrows equipped with a muzzy broadhead.
The results were pretty conclusive. The vest barely stopped the compound bow. However, the crossbow tore right through and penetrated the torso. Check out the Video.
I actually found this a little surprising. I searched the internet to find a reason and my question was answered by a contributor on the site Quora.
“Basically the problem is that blades (knives, arrowheads, etc) work differently from bullets. Or more to the point, the aramid fibers (such as Kevlar) that armor is made from work differently.
Bullets don’t cut the fibers, they try and force their way between them. The aramid weave is made in a way that forces the bullet to try and stretch the fibers, and they have very, very high strength in that direction. That’s how you can have a vest that is flexible(ish) but which stops bullets.
Blades don’t act the same way, they simply cut the fibers. So most “bulletproof” vests can actually be penetrated by a good hard stab from a knife or being shot with an arrow. To make a vest stab-resistant means adding layers of metal or very hard plastics. The very best bulletproof vests (typically those worn by soldiers who are facing rifle bullets) have additional plates of titanium or ceramics, which are more than hard enough to make an arrow simply bounce off. If you catch the arrow on one of those plates, that is…
So yes, either a non-bulletproof stab vest or a stab-rated bulletproof vest should perform well against an arrow. How well would it perform? Well, they’re not really designed to stop arrows. One of the top-level stab ratings calls for resistance to a stab with 43 joules of kinetic energy, while a decent bow would be 50–100J. Depending on the range, type of bow, angle of impact, etc I’d say there’s a decent chance of still getting an arrow stuck in you, but it’ll certainly take most of the punch out of it and it’s got a fair chance of stopping it.“