I did not think that the M60 was being used much anymore, and I thought this was ridiculus, because a .223 SAW is pathetic.
This story comes from early in the Afgan war, and standard issue was this lighter bullet (something like 60 gr.) as situations similar to this continued to occur, commanders would specially import the old, bigger bullets for their troopers. I have only heard mixed information, but many seemed to prefer the older bullets and they apparently had much better performance, especially knockdown.
If you can, define "accurately" 600m.
Going to the .223 allows every man to carry the same cartrige, so they are interchangable with all weapons in the squad, including the M-249 SAW. This is one of the few positives of the .223, along with less recoil and it is easier to shoot, especially on auto. I would rather have our troops be able to fire 10 good shots from a .308 than just spray 150 rds from a .223 in the general direction of the enemy. I hope their are other good reasons for going to the .223, or America is in even more trouble than I thought.

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Weapons are cool.