Needed? No.

Quoted: Well, are they?

nope

No, not needed.

Quoted: Quoted: I think there is something about this in Black Rifle II but my copy is in the other room and I don't want to get up and look. I seem to remember some fuzzy quote about M4 ramps being needed for 77gr loads, but that sounds like BS to me. Found it here. "The extended feed ramps were necessary to ensure that the thin-jacketed 77-grain Match King bullets were not damaged during the feeding cycle." While not the resident expert on the issue, this makes absolutely no sense to me.

You may not be an expert, but your BS detector is tuned properly, because this particular BRII factoid is flat wrong.  Of course, the book contridicts itself on this point; earlier they talk about how the extended feedramps were added during a test program for the M4 in the early 90s, which was long before the 77gr ammo was being used by any troops (except marksmanship teams in non-combat rifles).  The 77gr ammo was used experimentally in 2001, and formally adopted in 2002 as Mk262, and 2003 as Mk262 Mod1.  Also note that a large percentage of the rifles currently shooting Mk262 ammo in combat do not have the extended feedramps.

-Troy

Quoted: So, it was because of the ogive on the M-855 that the ramps were adopted? And only on the M-4?

No.  The extended feedramps were adopted because it was found that the faster cyclic rate of the M4 (which is due to the shorter gas system and higher port pressure) could "beat" the mag follower/ammo during cycling (especially full-auto, which runs faster as the gun heats up), so that the ammo stack in the mag wasn't fully to the top by the time the bolt started feeding the top round into the rifle.  This caused the round's nose to hit low, occasionally causing jams and bullet set-back.  The problem was exaggerated in arctic testing, where the cold further slowed the mag spring/follower.

It was found that by extending the feedramps, the rifle would "tolerate" the slowness of the ammo feeding because the lower feedramp would "catch" the bullet's nose and guide it up into place.  
They also help the rifle "tolerate" out of spec or damaged mags that don't feed the ammo exactly right.

Of course, it also helps in feeding shorter bullets, such as many hollowpoint and softpoint designs, which tend to hit lower than FMJ due to their shorter length and the geometry of the bullet feeding, but this wasn't the primary consideration for the military, which uses FMJ ammo 99+% of the time.

-Troy

Direct quote from Colt's 1994's flyer / spec sheet on the Colt Model 723 and Model 727 M16A2 Carbines;

Redesigned Feed Ramps facilitate feeding of both military specification as well as commercial ammunition

JohnM at Home