Quote:
Originally Posted by HistoricalDavid
Doesn't the 20-inch barrel exploit the fragmenting tendencies of 5.56 better than the 14.5 inch via higher velocity?
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Well, generally, yes, you will get higher muzzle velocity and improved accuracy from a longer barrel. Since the round has to be above a certain fps to fragment, you get a greater distance at which this can take place. Of course, like anything, the design of a battle rifle/carbine involves trade-offs in these regards. It's far easier to move an M4 with a collapsed buttstock and shorter barrel around vehicles and inside confined spaces. It's also a bit nicer to jump with and carry as a dismount. Meanwhile, the difference in performance for an average shooter may not be enough to justify keeping the longer barrel for many parts of the Army, particularly when most of your engagements are happening at under 200 meters.