jason, one decree is equal to 17.7 mils.
if you saw the GTA (graphic training aid) that i put as a pic in the tread sh3 grid protractor, you will see a square protractor, i and many use for indirect fire, and land navigation.
the outside edge is in mils, there are 6400 mils in a 360 decree circle.
there are 360 decrees in a circle.
the math to find how many mils in one decree is,
6400 / 360 = 17.7 mils.
check this out.
http://www.maptools.com/products/UTMGrids.html
using mils is alot more accurate and precise than decrees.