What about the SAW? It fires the same round (I believe) as the M-16, but is rated effective out to about 1000 yards.
I defer to those who have lugged the 22 pounder around.
The reason the SAW is effective out to that rate is because it's spraying out a high volume of fire. Technically, the M16 is good out to that range if you can see what you're shooting at and can see where the rounds land. The maximum range of the M16 is over 3500 meters. Effective range is only 550 though. The 50 Cal has a max range of over 6 kilometers but the effective range is 1800 meters. That's over a mile. The thing with the 50 is, you can legitimately
aim at things that far away and hope to hit it.
The barrel for the 50 is almost 4 feet long. This accounts for most of this accuracy. The thing with the M4 is- you're losing barrel length. That's what makes it less accurate than the M16A2 at range.
The SAW weighs more like 16 pounds empty. 22 is including 6 lbs of ammo; close to what the general-purpose MG (formerly M60, now M240) weighs empty, but the 7.62mm ammo is a LOT heavier. Twice as heavy, in fact. In practical terms this means a soldier or combat unit has half as much ammo with .30 calibre weapons.
Some SAW links
http://www.armystudyguide.com/m249/studyguide.htm http://ppt.armystudyguide.com/weapons/5.htm http://remtek.com/arms/fn/minimi/ (the second link is an excellent Peter Kokalis [I think] article that tells the history of US squad auto weapon development, back to the BAR). One error, the M249 is not reliable with M16 magazines and we've given up using it that way.
Any machine gun is rated as having a greater effective range than a rifle of the same calibre. This has to do with the way MGs are employed versus the way rifles are. You can definitely keep people's heads down, or tear up a group of them, with a .50 MG at ranges that would render a Barrett useless, for example. With the Barrett you are trying to get a message to an individual, with an MG you are sending a lot of mail to "occupant"!
d.o.l.
Criminal Number 18F