While I've never had any time behind an A1, I've had a decent amount of time with the A2.  Some changes are understandable, like the brass deflector so left handed people can use the rifle, and changing the forward assist button to a circle to save money and make it stronger.  So why did the chnage the other things?  I know the Marines are the only branch that actually use their elevation wheel to go out to 500m, but I could never ever see myself touching that think in combat.  Secondly, why the heavier barrel?  Only a small portion of it is heavier, but it sure adds a lot of weight.  It seems like taking away AUTO and replacing it with BURST would be even more of a reason to stay with the pencil barrel.  The buttstock was lengthened to a size that most people feel is too long, especially once you've got on layers of armor, clothing, etc.  The pistol grip added that little hump between your  middle and last two fingers, and all it does is give me a blister.  Handguards a debatable, but I would think that the older ones would serve a better purpose as the bottom is flat, so you could rest them on a ledge or in the palm of your hand to get a more solid platform to fire from.  A1 to A2 birdcage makes sense.  Does anyone have any opinions on why things were changed the way they were?  Today, it appears as if the whole XM8 program even started was to lighten the weight of the rifle.  The original AR15 was something like 6 pounds with a full 20" barrel, right?  Now the M-16A2 is approaching 8 pounds.  That's a huge difference.

Quoted: ... An M16A2 weighs 8.3lbs ..

FYI The postban HBAR A2 was roughly 8.3 pounds unloaded.  Standard Military M16A2 sans sling or magazine is 7.5lbs.

The reason the front of the barrel was made stronger was to make it harder to bend when some dumbass uses it as a pry bar.

Do you guys really think this is true? Is there any indication at all thet there were a bunch of bent A1 barrels? Besides, if you tried to pry something with an A2, wouldn't it just bend behind the gasblock anyway? The weakness is still there, just moved back a bit.

I have a personal unsubstantiated theory that they wanted the stiffer HBAR (because the Marines wanted a target rifle), but then after the project got along a while and everybody got a look at that thicker, stiffer, more accurate barrel, somebody realized that the M203 wouldn't fit the fatter barrel and/or a bunch of people complained it was too heavy. So they just "fixed the glitch" by reducing the diameter where the '203 goes rather than admiting they were wrong about the whole HBAR business. The thinner part was hid nicely under the handguards lest the mistake be obvious to the casual observer, somebody gets a raise/bonus/promotion and Colt gets a nice fat Govt. contract.