Bullet proof armor

There used to be the Higgins Armory Museum out in Worcester Massachusetts.  Big building, three or four stories tall.  All filled with medieval plate armor.  The museum was put up by a Yankee millionaire who liked to collect armor.  His collection is what filled the museum.  I took my kids out the Higgins a couple of times.  They loved the place. Unfortunately the money ran out a few years ago and they had to close the museum.  A great loss.  

   Higgins did show that plate armor was bullet proof.  Most of the suits bore a proof mark, a bullet mark where the maker had tested the armor by firing a bullet at it.  As time went on, guns grew more powerful.  There was a suit of plate armor at Higgins that sported the proper proofmark, but also sported a big bullet hole in the breast plate.  That bullet probably killed the wearer.   

   Early suits of plate were "cap a pied" French for head to toe.  These had plates protecting arms and legs, including lovely plate armor shoes to protect the feet.  One of these suits would keep out Robin Hood's arrows all over.  Guns hit harder than arrows, and in the 1400's when muskets came into use, they had to make the breast plate thicker to make it bullet proof.  To keep the weight down they dropped the cap a pied and left arms and legs unprotected.  The thinking must have been that a bullet in the torso was probably fatal but a bullet in a limb, while a bad wound, was survivable.  

   By the 1700's the muskets were powerful enough to pierce any plate armor light enough to wear, and so troops stopped wearing armor and just went into battle wearing a colorful cloth uniform.