We always use the standard Lensatic compass instead of the M2. The M2 you have declinate/orientate to your area. They usually have a compass
"zeroing" point or orientating point set up prior to starting the task. With the protractors you also have to look at how they are cut. What I mean is, you look at the 1/50,000th scale(common military map scale) and you check to see if the triangle is evenly cut. If is not it can throw you off big time especially for the non -Artillery types who use degrees instead of mils. (17.7777777777 or 17.78 Mils per degree) Mils is way more accurate. It happens Junky. I am no pro when it comes to being a stick in Aces but I do know land nav.