Ok so I've been doing some research recently about armor and firearms, and I thought I'd share some of what I've found here. What I was trying to figure out was how well armor protected against the firearms of the 15th Centruy, in the 16th Century, and afterword in the 17th and 18th Century.
My primary source for armor is an excellent and in HEMA circles somewhat famous book called [ame=http://www.amazon.com/Knight-Blast-Furnace-History-Metallurgy/dp/9004124985/ref=sr_1_1?ie=UTF8&s=books&qid=1276098125&sr=8-1]The Knight and the Blast Furnace[/ame]. Unfortunately for me a copy of this book runs about $300 (if you can find it). But foruntely for me, a partial transcription of the book is now available on google books.
Here is the google books for Knight and the Blast Furnace
The knight and the blast furnace: a ... - Google Books
What makes this book so remarkable and valuable to researchers like me is that the author, Alan Williams, spent 30 years travelling to Museums around the world with a microscope and durometer and a variety of other tools, and measured the thickness, hardness, metalurgy, and chemical composition of over 600 pieces of antique European armor. He is to armor kind of what Ewart Oakeshott was to swords.
So he is a terrific resource if you want to know the reality of armor. As a baseline for Williams wor, to start with, I wanted to look at some modern armor. This modern commercially available armored plate:
http://www.mtlgrp.com/pdf/Armox-Armour.pdf
...can, according to the trade lit linked above, stop a .357 magnum at 5 meters with 3mm thickness, or an M-16 5.56 / FN-FAL .308 at 10 meters with 6mm thickness (almost half an inch).
This is a medium tempered steel alloy with .3% carbon, and trace amounts of molybdenum, nickel, chromium, and mangenese which they say gives an 'equivalent carbon content' of 0.67%. The steel has a hardness of 480 - 540 HB.
I wanted to compare that hardness to the numbers quoted in Knight and the Blast Furnace. Alan Williams uses the VPH scale. So for example on page 379 of Knight and the Blast Furnace there is a 15th Century Tempered German breastplate listed with an average hardness of 405 VPH which translates to about 380 HB, if I'm reading that right, which seems to be in the ballpark (76%) of the average hardness for the modern armor cited above. Unfortunately Alan doesn't list the thickness of the specific plate, but in the 15th Century it rangd from about 1.8 to 3mm depending on where on the armor it was.
So it seems to me that this 15th Century armor was probably sufiicient to protect against a .357 magnum at medium range, which is somewhat surprising
On page 409 there is another similar half-armor, tempered steel at 0.5% carbon with an average hardness of 408 VPH
Another similar tempered steel three quarters anime harness on page 414 has an average VPH of 407 and a carbon content of 0.5%
I was using this table for conversion:
Steel Hardness Conversions
NEXT: comparing armor to the muzzle energy of hand-culverins, arquebuses, muskets and modern firearms and 15th, 16th and 17tth Century armor.
G.
