I stand corrected, there does seem to be an angular difference between the two reticles. Those infantry guys just have to be the odd men out. However the difference is insignificant compared to the dimensions of the dots and ovals.
ARMY: 3.375 moa multiplied by 1.047” x 10 = 35.3” @ 1000 yards
USMC: 3.438 moa multiplied by 1.047” x 10 = 36.0” @ 1000 yards
Both Army and USMC snipers have the goal of estimating to the tenth of a mil to get an accurate range estimation, and the difference between Arty and True is insignificant inside direct fire ranges. For the purpose of Artillery launching a projectile over 15 kilometers that difference becomes significant. Over a thousand yards the difference is a bit less than that, however for the purposes of direct fire by a sniper, not so much as you can see by the math.
So every sniper (Army B4 or USMC SS) whether they are using Army or USMC scopes is going to use the same range estimation formula, which is why the "mildot math" works no matter which reticle you happen to be using.