Because if you replace the 200 round SAW with a 100 round IAR that is a down-grade in capability. You have half the volume of fire and you will have to reload twice as often. I also thought I'd throw out the fact that belts are much more reliable then drums. Drums tend to jam way to much. There is a reason why the U.S. Military went for the 200 round belt feed SAW.
The 200 round box for the M249 was actually one of it's greatest flaws.
The belt tends to rattle in the box (especially once you've fire the weapon, and you have less than a full belt inside) making noise discipline a problem. A field expedient solution has been to open the box and stuff pieces of carboard along side the belt, which helps but is hardly an ideal solution.
The spring loaded plastic tab on the box that attaches to the M249 is weak. Boxes have a annoying tendency to become detached at the least opportune moments. They are easily snagged when moving through heavy vegetation or crawling on the ground. Anyone who as carried a M249 for any length of time in the field has learn to dread the sound of the belt zipping out of the box as it falls to the ground or gets hung up on something. Putting the belt back in (correctly so with will feed back out smoothly) is, not suprinsingly, a pain in the ass.
Carrying the 200 round boxes can be a pain as well. Originally, the were left in the cloth "bandoliers" that they are shipped in and slung across the body. These of course bang around, rattle, and generally get in the way. Later the Army began to field saw box pouches for the LCE and later LBV which helped, but again the boxes still rattled in thier pouches, and having two full saw box pouches attached to the front of your LCE/LBV was hardly comfortable.
The US Army has come up with an excellent solution to these issues, a 100 round, soft cloth belt "bag" refered to (if you'll excuse my vulgarity) as a "ball bag" or "nut sack". Being made of nylon cloth, it is silent, it has a zipper on the bottom for ease of access, and a metal clip for more secure mounting on the weapon. They have been in use for several years, and are very popular. Odds are, if you see a photo of a US Soldier in Iraq or Afghanistan with an M249 it will have the 100 round soft pouch on it. The 200 round boxes are more commonly used when the M249 is mounted on a vehicle, or employed in a static, defensive role, such as in a tower or at a check point.
So I think the argument that the 100 round drum is "a down-grade" is really a moot point. 100 belts are the most common load out for the M249 these days anyways.
I'm not really sure of the value of an IAR per the USMC requirement. I'd be interested to see how they would integrate the weapon into thier infantry squad TO&E. As a 1 for 1 replacement for the M249, I think it would be a mistake. An IAR with a fixed barrel simply lacks the kind of sustained fire capability of a SAW for suppressive fires. If the IAR would be an addition to, rather than a replacement of the M249 - to provide the squad with added fire power in circumstances where using an M249 is less desireable, such as CQB, then I could see the utility of the weapon - though I'm not sure it justifies the expense of adding another weapon system to the inventory.
I'd like to see the M249 replaced with the lighter MK 46 Mod 1 - similar capabilities, less weight.
FYI - I've been in the Army & Army NG for 14 years, primarily as an infantryman, and have used the M249 extensively in many different enviornments. Overall good system - and IMHO most of its flaws are remedied by the MK 46.
Adrian
