Pop-history has been responsible for perpetuating the notion that the most effective machine gun employed in world war 2 was the MG 42. Most people know the specs of this fine weapon, but lets run through them again for clarity: It was a 30 caliber machine gun that was usually mounted on a tripod, fed from a disintegrating ammunition belt, and fired at the incredible rate of 1200-1500 rpm. (The bren gun used by the british was magazine fed, and only fired at 500 rpm by contrast) The wall of lead that came out of this weapons barrel left a deep mark on many allied soldiers, and the MG 42 made prominent appearances in many postwar movies and memoirs. What many people don't seem to have considered is why the german high command selected a machine gun with such an unusually high rate of fire. It went against their strict doctrine of ammo conservation, which demanded that a weapons cyclic fire rate be kept artificially low (so that even during a mad minute, ammunition quotas would not be exceeded).
Most sources on this matter will assert: ''The high rate of fire resulted from experiments with preceding weapons that concluded that since a soldier only has a short period of time to shoot at an enemy, it was imperative to fire the highest number of bullets possible to increase the likelihood of a hit... The disadvantage of applying this principle was that the weapon consumed exorbitant amounts of ammunition and quickly overheated its barrel, making sustained fire problematic.'' Or this: ''The germans however came to the conclusion that a soldier in combat only fires when he sees the enemy and has but a few seconds to do so, taking this as a medium for all combatants they deemed it was he who fired an increased amount of bullets had an increased chance of a kill.'' But is there any truth to these explanations? An essay penned by our resident military guru, jim storr, suggest there is a completely different criterion that is not being accounted for.
Pondering the vast number of rounds per kill that are expended over the course of an engagement, like the notorious 250,000 bullets per KIA in iraq and afghanistan, storr suggests that something is interfering with a modern armys ability to employ small arms fire. This goes beyond things like stress and return fire making our troops accuracy levels decreases. Indeed, even if we accept that most of the shots fired off in a battle are done only to supress the enemy and not to kill him (since soldiers conceal themselves, they are hard to hit), this cannot explain how a quarter million rounds are expended just to kill one soldier: The only explanation is that the suppressing fire itself is being delivered in a fundamentally incorrect manner. Back in 1944, a study carried out by the army operational research group concluded that projectiles must not only pass within a certain proximity of a human combatant, but also arrive in a certain volume before he will feel threatened enough to take cover.
These are quantifiable data points that allow us to measure how much success a weapon and its user are having in a firefight. Armed with this knowledge, a group of soldiers from the british army were sent onto the firing range to train on a new piece of equipment, the live fire intelligent target. The results showed that most rounds fired missed by too wide a margin to drive an enemy to the ground, and that ammunition was expended at too high a rate to be sustainable for more than a few minutes. Thats consistent with what we have seen of other armys engaged in armed conflict: Infantrymen are not trained to excel at the role of suppression, nor do they have the proper weapons. The training problem can be solved by offering courses like those available at the TTECG, and giving sergeants stricter protocols for fire control. Of course, this still leaves us wondering what kind of small arm is best suited to suppression. If you thought it would be a belt fed, sustained fire weapon (with a quick change barrel) like the MG 42 or minimi, storrs response will come as a dissapointment:
''The British L86 magazinefed SA 80 Light Support Weapon (LSW), with its bipod, is extremely good at suppressing targets out to 500m or more... That is principally because it is accurate enough for almost every shot fired to contribute to suppression. The L110 (Minimi) Light Machine Gun (LMG) performs far worse in such trials. At best, only the first shot of a short burst passes close enough to suppress. However, subsequent shots in that burst go anything up to 6m wide of the mark at battlefield ranges.'' There is something very important that mr storr neglected to consider, however. And that is the combat role that infantrymen have in mind for their machine guns. In WW2, the germans placed a greater emphasis on engaging area targets, while the british focused on suppressing point targets. Not surprisingly, they both selected very different weapons prior to entering the war. The MG 42s wide cone of fire enabled it to suppress groups, while the bren guns narrow cone of fire enabled it to suppress individuals. Both were successful in fulfilling their combat role, but that brings another question to mind: Which philosophy (area targets vs point targets) is the correct one?
Before we can answer this dilemma, there is an important reality of the battlefield that must be borne in mind. Ever since the adoption of the rifled musket in the mid 1800s (and then the breech loading rifle in the late 1800s), armys have been forced to abandon close order formations and disperse themselves in order to survive weapons fire. The level of dispersion that occurred in this time frame is surprising. A book by trevor dupuy indicates that during the american civil war, armys were dispersed to the tune of 257 square meters per man.  During world war 1, the dispersion increased to 2475 square meters per man. During world war 2, the dispersion increased to 27,500 square meters per man. In other words, the amount of men in a given space (force densitys) decreased by a factor of 107 from the civil war to WW2. The trend towards increased dispersion has continued to accelerate. With that fact in mind, its hardly surprising that the number of bullets needed to kill an soldier has increased to such ridiculous highs.
Soldier of fortune magazine provides some figures on how much ammunition was expended per enemy killed in both world wars and korea.  Roughly 5000 rounds were fired for every enemy KIA in WW1, whereas 25,000 rounds were fired for every enemy KIA in WW2. In the korean war, the ammunition expenditure went up to an incredible 100,000 rounds per KIA. Thanks to this data, we can safely conclude that there is a strong correlation between force densitys and rounds per KIA. The more dispersed the enemy is, the harder they are to suppress and to hit. It seems that the old german practise of having their machine guns fire at groups (area targets) was a better compromise, and more reflective of the type of battle a soldier was likely to encounter. They got more mileage out of their mg 42s than the british did with their bren guns, and we should follow suit by focusing on crew served weapons with a wide cone of fire, like the current MG 3. We should also change the marksmanship training for soldiers, so that they are better able to use their rifles to engage individuals (point targets).
 Numbers, Predictions and War: Using History to Evaluate Combat Factors and Predict the Outcome of Battles, by Trevor Dupuy.
 Soldier of Fortune Magazine Guide to Super Snipers, by Robert K. Brown.