WOW! Lots of guys reading too many magazines!
The primary change to the 'A-2' was for the 3 shot burst so barrel overheating wasn't a problem like it was on the A-1.
Barrel overheating and ammo wasting is a problem to this day, but the 3 shot trigger is going the way of the Edsel.
"Hardened" (mono-crystalline) barrels that will take the heat MUCH better are on the way, but not past testing yet...
And anyone that had been on a range testing or in a firefight would know that THROAT EROSION is the reason the 3 shot burst was implemented...
A. Recruit 'Dilbert' gets scared and dumps mags as fast as he can get them in the rifle,
B. Barrel overheats and softens,
C. Softened barrel gives way at the point where chamber pressures & temperatures are highest, in the chamber throat and at the beginning of the rifling,
D. Erosion keeps rifle from cycling, and in some cases, causes barrel blockage and catastrophic failures in combat situations,
E. Military teaches Special Forces 'Operators' to pour canteens over barrels at the chambers to keep them cycling,
F. In stead of the military teaching 'Dilbert' some self control They change the trigger group to 3 shot bursts instead of fully automatic...
G. Operators didn't like being limited to 3 round bursts when trying to suppress an ambush, special forces troops killed, Military reconsiders the 3 shot burst idea,
H. Special Forces and most general military types wanted an 'M-16 variant' that could fire the 100 round drums all day long without having problems,
I. 'Heat Hardened' mono-crystalline barrels, along with many other ideas are cooked up to allow full auto fire without overheating...
But aren't through testing yet,
Although Germany and Austria have had them on SAW's for years...
Y, Because someone needs to tell the truth about this stuff...
Not just regurgitate what they 'Composted' from some magazine article or read on the internet...
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Along with the A-2 Configuration came the adjustable rear sight for elevation and easier controls for windage.
Elevation control on the A-1 was a 'R' (Regular) or unlabeled rear leaf,
And a 'L' labeled leaf. The 'L' was for 'Long Range',
The two holes were RARELY aligned in the leaves, so if you switched from one to the other, it moved your WINDAGE along with the elevation,
AND,
Nothing on the elevation was marked for range! You had to GUESS!
And flipping the leaves was the extent of the rifleman's ability to correct for range in a foxhole.
To correct for range, you had to turn the rifle around, and use a sight tool (or bullet nose if you were desperate) and screw the front sight up and down!
All that when someone is shooting at you! I DON"T THINK SO!
The A-2 brought in a thumb wheel adjustment for the rear sight
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Most of the A-2 Aperture leaves were either a large, open hole that was intended for NIGHT SIGHTS & CQB...
Althought the 20" barrel M-16A2 was NOT inteded for CQB, you COULD use the night sight as a CQB sight.
And the smaller hole in the A2 sight was intended for actually AIMING the Rifle beyond 50 meters.
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I, along with all the match shooters and Operators I know prefer the 'National Match' version of the A-2 sights,
Which have 1/4 MOA adjustment 'Clicks' to the windage,
(Instead of the 1/2 MOA clicks of the standard A2 sight)
AND,
Elevation adjustments are smoother and more accurate,
And you get 'Clicks' between 200 and 300, 300 to 400, ect,
Where with the standard A-2 sight you simply got 200,300,400, ect.
And the Aperture holes on the sight leaf are 'Small' and 'Smaller' for better accuracy farther down range.
In 'Operational' situations, We used to drill one out for night/CQB operations, but for the most part the National Match version of rear sight was MUCH MORE ACCURATE than the A-2 version was.
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The A-2 also saw the advent of the 'bump' so left handed shooters didn't wind up with hot brass in their collars!
I saw how the 'Internet Experts' foamed at the mouth, so maybe I shouldn't mention the change in the number of detents in the front sight or the switch from taper pins to roll pins holding the front sight/gas block on...?
And I'm afraid if I mention the changes in the one inch longer stocks, or improved butt plates some heads might explode...
If I say anything about the firing pin detent pin change or the extractor spring change there might be riots!
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To the OP's question,
No the A-2 isn't anymore 'Obsolete' than the A-1 or the orignal AR-15 or M-16's are.
They are, and will continue to be, just as viable 10 or 15 years from now as they were 45 years ago...
AND,
If we can keep some butt head in procurement from switching things without proper approval and testing,
the rifle will be viable 45 years from now!
(like switching from the orignal IMR Stick powder to ball powder or ordering under cut lighter weight barrels)
), so I may one day get a 20" upper with fixed, A1-style carry handle.
