Gil, not going to say the obvious but if you look at the two pics below, one I never posted but the machine gun turret is a swivel like on a german tank and the armour is sections of 3-4 inch plate set at different sizes to create the angle but is built up as an angle as opposed as a straight line angle,the walls must be at least 3 ft thick or greater, its a far greater ark of fire and sight compared to our pill boxes that had just the small opening but was on every side.

The particular bunker I guess had something on top also as there is a section that looks like its been removed and back filled, I'll get some more pics next week. but pics below of the built up section of the machine gun turret/swivel

Its a shame the shadow on the two pics as its clear in the flesh the hole for the MG 34 or 42 that went through the other holes I can say was for viewing or even had some form of sight , telescope ?