Machinegun Gunnery
With all our emphasis on rifles and pistols (and an occasional mortar tip) our machine-gunning friends have asked not to be left out. OK...here goes...you won't find this in most manuals...
SEARCHING and TRAVERSING REVERSE SLOPES
Bottom line: Once you've done the math and set yourself up to search a reverse slope, OMNA recommends tripling your ammunition expenditure before each adjustment in search or traverse. Here's why:
Most folks know that a medium machinegun such as the M240G fired from a tripod has a beaten zone about 2 mils wide. The length of that beaten zone is nearly 100 meters long at ranges less than 500 yards, and is about 50 meters long at ranges in excess of 1000 meters. So at a range of 1500 meters, the beaten zone would be 3 meters wide and about 42 meters long ON FLAT TERRAIN WITH THE TARGET AT THE SAME ELEVATION AS THE GUN.
If you are searching reverse slopes however, the terrain obviously is not flat, so you need to account for the angle of fall of the cone of fire and reconcile that with the angle of the reverse slope. Add in any compensation for vertical interval too. So chances are, that your beaten zone may be considerably longer than 42 meters! In fact, you might be getting some good grazing fire on the back side if you set it up properly.
So our point is this...if you're firing a 6 round burst from a single gun at 1500 meters, the cone of fire from that burst is covering a beaten zone of at least 150 square meters. or one round impacting in every 15x15 foot space, the size of a large bedroom. If you fire one burst and then immediately move on in your searching and traversing, chances are you won't hit much. So consider firing three bursts of 12 rounds before manipulating the lay of the gun, or massing fires of a section (6 guns) in a converged sheaf when searching and traversing reverse slopes.
Too bad graphic firing tables were excluded from the latest Marine Corps Warfighting Publication 3-15.1 (Machine Gun Gunnery), but most all the tabular firing tables are still in there.
Good shooting!
Shooting tips every month!
