If bullet proof vests are vulnerable to knives.

Edge of blade(s) will catch wind and bullet won't go forward.

File: tumblr_o1r77o4eXn1szqwnwo1_1280.jpg (353KB, 800x800px) Image search: [Google]

353KB, 800x800px

What if its shaped like this?

File: 61qA4sRoKiL__SL1500_.jpg (115KB, 1500x1500px) Image search: [Google]

115KB, 1500x1500px

>>29545142
or why not just use a crossbow?

>>29545489
Would be insanely expensive.

>>29545142
they have pointy bullets already

>>29545481
Just add pop-out flights

File: 1368770985-fn205720mi-o.jpg (137KB, 800x500px) Image search: [Google]

137KB, 800x500px

Do you honestly think this gun is only for show?

*don't mind the blue tip

>>29545489
That is one evil looking knife. I hear you'd bleed out in mins if you got stabbed with that one.

File: FRANKA.jpg (224KB, 664x1000px) Image search: [Google]

224KB, 664x1000px

>>29545142
Got you famalam

Physics and material properties.

The soft armour works like a non Newtonian fluid, a fast projectile with a lot of energy is caught in the layers of material that each absorb a bit of the energy.
A knife can cut Kevlar because it is slow.

Also, hard plates.

Also, stab inserts only add three pounds to the armour.