I had read a lot recently about how it's not just the overall weight of a rifle that matters, but how well the rifle balances.  "Balance" meaning the center of gravity in reference to the overall length of the rifle.  So it got me to thinking about my Colt 6920 setup, and how I hated the way it felt so front-heavy.

I had this rifle configured with a Surefire 6P with Malkoff M60 in a DD mount, and a LaRue FUG attached to my rail.  Although the 6P with Malkoff is a great light, it's a serious chunk.  Also built like a tank is the FUG, making it one of if not the heaviest quality VFGs I've handled.  With all this weight up front, I was running a Magpul CTR stock in the back, which is relatively light-weight, not much heavier than the standard M4 stock.  This configuration brought the overall weight of the rifle to almost exactly 10lbs when loaded with a 30rd pmag.

Here is that rifle in it's front-heavy configuration:



So, I replaced the 6P in the DD mount with a Surefire X300, and ditched the FUG.  I also removed the front side sling swivel mount (the entire assembly, not just the swivel) and replaced it with a QD swivel attached to the rail's built-in swivel socket.  Lastly, I replaced the CTR with an LMT SOPMOD (which I immediately fell in love with btw).  The X300 weighs less than half of what my previous light and mount did, and by also losing the FUG and side sling swivel assembly, the front-end of the rifle is considerably lighter. However, the SOPMOD is noticeably heavier than the CTR, especially with a couple 123 batteries and a few bottles of machine gunners lube stowed in the storage compartments.  All other components remain unchanged.

When I first picked up the rifle with it's new configuration, I was sure it was at least a pound if not lighter than previously. It's not front-heavy and feels down right handy.  However, with a loaded 30rd pmag, the rifle weighs almost exactly the same as it did before the transformation, 10lbs. The difference is that the rifle's center of gravity has shifted rearward by taking weight away from the front and adding it to the rear.  The rifle is just as equipped, it still has a quality light, quality stock, front sling attachment, and storage.  So the bottom line is, balance is just as important as overall weight, as it can make two equally equipped rifles of the same overall weight handle and feel VERY different.

Here's the rifle now in it's better-balanced configuration:

You are correct.  I've been trying to explain this for years.

Of course, I like lighter stocks and barrels.  Same balance, but a pound lighter....

Me too but it seems like most people aren't listening.

There are a lot of ways to accomplish that goal, lighter accessories and rails out front, heavier stock and buffer in the rear. Matter of fact, I always use 9mm buffers in my carbines because they not only help balance the weapon but they also lower felt recoil and (at least in theory) improve the reliability of the weapon. The 9mm buffer is a win, win, win IMO.

On the front end, I am very picky about what rail I use. Some Most are very heavy. Lighter profiles and shorter barrels help but that's a tricky situation because many people can't legally go below 16" and heavier profiles have their advantages too.

The FSB itself is a heavy little pig. I first realized that when I started playing with mid-length carbines because even though a "gov't profile" 16" midlength barrel itself is technically lighter then a 16" M4 profile barrel, the middy barrel feels more front heavy because of the FSB being further out. Now I use to be a big believer that a "fighting" AR should have a fixed front FSB but because of the weight\balance issue and because of how reliable modern combat optics have become, I've become a bigger fan of cut down FSB's (which retains the important taper pins) with a longer rail that covers the (now) gas block and a folding front site like the Troy. Not only is it a slick look that give you more real estate for whatever but it's also lighter out front (depending on rail used of course)

ETA - Here's an example of what I'm talking about. My 16" M4 is very similar to your original config but mine balances perfectly on the mag well. Why? Because I used a 9mm buffer out back and lighter rail and and light mount out front...

Not much lighter.  You lose about four ounces and you make two back up.

Better option is shorter barrels all around.  16 is the longest that I like.  12.5 would be better.

loose 4 here, add 2 there..it all matters in the end but I do agree, if you can go shorter then do it... Here is my main go-to rig and even with all the bells and whisles, the weight, balance and handling are all great IMO...

I'm the guy who doesn't like the forward assist because it weighs two ounces...

OK - you win. I don't get that anal about it!

That and I'm more worried about balance then I am overall weight and considering the FA's position, loosing it wouldn't effect that balance much if at all?

I'm a firm believer of balance vs. lightweight as they are two different issues. Contrary to most, I like rifles who's weight is biased towards the front. In casual carry mode, hooking a single middle finger of the weak hand under the Delta ring and carrying it down by my side, my heavier than lightweight AR seems to float in my hand. It also finds it's level faster when shouldering and locks on target better than a light front end.
I agree with upgrading from a hanging flashlight to an X300 rail light.

I want a beater KISS 14.5 but I want a SOCOM bbl. (heavy under the HG) to put some weight forward.
I may just get a Tac Entry and have ADCO shorten/pin it although I noticed BCM is coming out witha 14.5 SOCOM
in the near future  

A few observations:

1. When shooting national match, a bit more weight forward aids stability shooting off hand as well as rapid fire.

2. When shooting moving targets, a bit more mass up front helps it track and follow through a bit better.

3. When the A2 came on line, many troops preferred the slightly forward weight distribution when firing, but the effect was subtle.  With the A1 the rifle balanced at the center of the mag well with sling ,cleaning kit and loaded 30 round magazine. The A2 balanced at the front of the mag well in the same configuration.  My impression was that it had a lot more to do with the great mass farther forward, not so much the balance, and you paid for that with greater mass over all which slowed the rifle down getting on target. In semi-auto it makes a lot less difference.

4. My 5.7 pound lightweight slick side 16" carbine also balances at the front of the magwell and it is my favorite weapon for tactical matches - very lightweight and slightly biased toward the front in terms of balance.

5. When you start adding things on a rail (optics, light, etc) , you also move the center of gravity much higher on the weapon and it compromises a great deal of it's handling qualities.  

Keeping your support hand close to bore centerline helps to control things.

I like Aimpoint Micros.

High five for a well-balanced carbine.  I'd rather lug around a well balanced 20 lbs gun than a front heavy 10 lbs gun.  Of course, what I really like is a well-balanced 10 lbs AR.

If it weighs twenty it's gonna have a belt.  Even my AI weighs less...