This is the official word from Winchester about what is different between the USA223R1 and the Q3131A.  It mentions nothing about the bullet being different between the two rounds.  I'm not saying they ARE the same but now I have to write them back to the the official word on the bullet.


.223 Rem VS 5.56mm

There are a lot of questions about these two cartridges.  Many people think
they are identical - merely different designations for commercial and
military.  The truth is that, although somewhat similar, they are not the
same and you should know the differences before buying either cartridge.

* The cartridge casings for both calibers have basically the same
length and exterior dimensions.
* The 5.56 round, loaded to Military Specification, typically has
higher velocity and chamber pressure than the .223 Rem.
* The 5.56 cartridge case may have thicker walls, and a thicker head,
for extra strength. This better contains the higher chamber pressure.
However, a thicker case reduces powder capacity, which is of concern to the
reloader.  
* The 5.56mm and .223 Rem chambers are nearly identical.  The
difference is in the "Leade".  Leade is defined as the portion of the barrel
directly in front of the chamber where the rifling has been conically
removed to allow room for the seated bullet.  It is also more commonly known
as the throat.  Leade in a .223 Rem chamber is usually .085".  In a 5.56mm
chamber the leade is typically .162", or almost twice as much as in the 223
Rem chamber.
* You can fire .223 Rem cartridges in 5.56mm chambers with this longer
leade, but you will generally have a slight loss in accuracy and velocity
over firing the .223 round in the chamber with the shorter leade it was
designed for.
* Problems may occur when firing the higher-pressure 5.56mm cartridge
in a .223 chamber with its much shorter leade.  It is generally known that
shortening the leade can dramatically increase chamber pressure.  In some
cases, this higher pressure could result in primer pocket gas leaks, blown
cartridge case heads and gun functioning issues.  
* The 5.56mm military cartridge fired in a .223 Rem chamber is
considered by SAAMI (Small Arm and Ammunition Manufacturers Institute) to be
an unsafe ammunition combination.

Before buying either of these two types of ammunition, always check your gun
to find what caliber it is chambered for, then buy the appropriate
ammunition.  Most 5.56mm rounds made have full metal jacket bullets.
Performance bullets - soft points, hollow points, Ballistic Silvertips, etc.
- are loaded in .223 Rem cartridges.  Firing a .223 Rem cartridge in a
5.56mm-chambered gun is safe and merely gives you slightly reduced velocity
and accuracy.  However we do not recommend, nor does SAAMI recommend, firing
a 5.56mm cartridge in a gun chambered for the .223 Rem as the shorter leade
can cause pressure-related problems.

____________________________________________________
Don't fight a battle if you don't gain anything by winning.
Erwin Rommel

I can almost gaurauntee the bullets are different.  Like you said the brochure shows different ballistic coefficient.  I don't have two to sit side by side but the bullet in the q3131a to me looks different.  I have a umc 55 fmj next to the q3131a and there's no question they're different.  I know it's not the white box.  If you want I'll send you a q3131a and you can compare the two if you got the usa white box.

Thanks, but let's just wait on the bullet and see what Winchester says.  

Troy says . . .
[i]Q3131A is made in Israel by IMI, using IMI components (even the WCC-stamped brass is IMI brass).

The USA223R1 and other FMJ loads are assembled in the US using Czech S&B copper-jacketed bullets. S&B supplies the gold-colored bullets, which leave gold-colored flakes everywhere, used in all of the pistol bulk-packs too.[/i]
. . . so hopefully Winchester can confirm this.

Can't you just change the uppers?

What are you talking about?

OK.  Just to confirm what they say, I have Q3131A and it says made in isreal on the boxes.