u/Brown_Colibri_705

An excerpt:

>On the surface, the idea of augmenting the firepower of a rifle squad with a belt-fed machine gun makes a good deal of sense: The feeding mechanism of the belt-fed means that many, many more rounds can be fired before the gun needs to be reloaded. The M249 itself is famous for its 200 round belt-in-box magazines which clip under the gun, and provide continuous firepower that a magazine-fed weapon simply would be unable to match. In theory, the addition of a weapon like this to the rifle squad should substantially augment small unit firepower and flexibility – especially on the defense where SAWs can be used to provide interlocking fires. And in theory, the SAW can be used like a rifle, too, so it’s win-win, right? Well, theory is different than practice – in this case, very different.

>One of the primary shortcomings of the SAW concept lies in the way target suppression works, and the weight-limited nature of the rifle squad. Fundamentally, the belt-fed SAW is a volume of fire weapon which achieves target suppression via probability. Put simply, more bullets flying means a higher chance to hit, and a higher chance to get close enough to keep the bad guys’ heads down. Thanks to its open bolt and interchangeable barrels, however, the SAW trades the rifle’s ability to make precise shots that suppress much more efficiently, for the absolute maximum possible fire volume. This makes the SAW an incredibly wasteful weapon that burdens the the squad with (literally) thousands of rounds of extra ammunition needed just to feed the two belt-feds. The rifle squad fireteam (4 men) of the United States Marine Corps is very similar to that of the US Army fireteam, with one exception: Where the US Army uses SAWs, the USMC instead employs a magazine-fed automatic rifle, the M27 IAR. The USMC automatic rifleman (AR) typically carries 11 magazines, and the other Marines in his fireteam carry 7 a piece. In the Army’s arrangement, each rifleman carries the same 7 magazine loadout, but on top of that they carry 200 round belts for the SAW, while the Army SAW gunner himself carries nearly 800 rounds of linked ammunition to feed his thirsty weapon. This additional ammunition amounts to an average increase of 3 kilograms (6.6 pounds) per soldier, or about 100%, in the US Army rifle squad fireteam, versus the USMC fireteam – a weight penalty equivalent to pure-fleeting 7.62 NATO rifles! Therefore, the abandonment of the SAW in favor of the much more efficient automatic rifle would result in substantial reductions in weight carried, while maintaining effectiveness through much greater precision of fire and much more judicial application of the fully automatic fire mode.

>Mobility may not seem as important for a role that is seen as supporting the squad, but ultimately it is one of the key shortfalls of the SAW concept. A belt-fed weapon is not only much heavier, but its ammunition handling is far inferior, and it is much more prone to jams when used as an organic squad weapon than the rifle. Exposed belts drag in debris from the environment, open bolts and open top covers (necessary when reloading) allow dust and filth into the weapon’s chamber. In a 2006 study on soldier weapon reliability, the M249 SAW was rated the least reliable individual weapon in the US Army inventory, and soldiers reported that stoppages with the M249 more than any other weapon had a large impact on the battle due to the time it took to clear them. This means that the SAW gunner must stop and clear malfunctions much more often than his teammates, and that weapon administrations are much more difficult, and take longer. Because of this, the SAW gunner often has difficulty keeping up with his fireteam, resulting in the unit being “tethered” to his position. Therefore, the mobility of not only the automatic rifleman is reduced by the SAW, but the mobility of the entire unit. Like the proverbial herd of buffalo, a squad can only move as fast as its slowest member.

>Reservations about the magazine-fed automatic rifle are unfounded, as well. The SAW’s most obvious advantage versus its mag-fed counterpart is, of course, ammunition capacity. 200 rounds beats 30, or so the logic goes. In reality, however, a 200 round soft pack is extremely heavy, about 3 kilograms (6.7 pounds) by itself. This makes a gun that is already difficult to maneuver and carry even more cumbersome. For this reason, often 100 round and 50 round soft packs are preferred over the 200 round boxes and soft packs, reducing this advantage by up to three-fourths. On the other hand, the significantly higher accuracy of a closed-bolt automatic rifle gives similar effectiveness to the belt-fed, open-bolt SAW, while using far less ammunition. USMC testing preceding the initiation of the Infantry Automatic Rifle program showed that a much more accurate weapon could achieve the same target effect as the M249, while using as little as 1/3rd the ammunition – a huge boon for weight-strapped infantry units.

Edit: Thought this might be nice food for thought and serve for an insightful discussion but never mind.