The pen is mightier than the sword, especially when it's made of a bullet. Behold, the Bullet Pen by Dorian Creations:
Dorian Creations Bullet Puns have clips in the shapes of rifles and are sometimes adorned with camo paint, but that’s not where the gunpowder stops. Each pen is crafted from a real life bullet. Not an artist’s representation of a bullet, a dyed in the wool, could-kill-someone .308 Winchester rifle round. Now you can – quite literally – seal the deal with a bullet.
Also, if this pen uses a standard ink cartridge, the shaft would have to extend through the primer hole (which would probably need to be drilled out).
A lot of time on their hands, when they weren't killing/dying for their country.
Even if someone did do it...any self respecting gun owner should realize that live ammunition is not a "toy".
Stupid is as stupid does.