You can't lighten a .30-06 BAR and expect to hit anything with it because it will be uncontrollable. In the 60's new versions of military weapons were all about weight. All of a sudden, to this present day, weight is a big issue that wasn't in both World Wars. We had to get rid of the M-14. Why?, weight. We adapted the M-16. Why?, weight.
The problem with this kind of thinking is it will only get you so far. In Viet Nam the shots fired to kill ratio went through the roof because GI's were blowing through ammo like crazy, hitting nothing in the process. Marksmanship went out the window in favor of "firepower". The problem with firepower is it is worthless if you don't hit anything, which our troops seldom did in Viet Nam. They sure did go through the ammo trying. And they did so in a weapon that was very "controllable".
In W.W.II the M-1 Garand held 8 rounds, and could not be topped off until it was empty. We won 2 wars in 2 separate theaters of operation, halfway around the world, in 2 totally different climate settings. Everything from steamy, rain soaked jungles to freezing European forests. Today we've yet to win a war with the M-16 platform. Yes, that can be attributed to other things as well, but my point is all of this "firepower" reasoning is flawed at best, false in fact. Look at todays police departments. Are they killing any more bad guys with 17 round Glocks and 20 round Sigs, than they did in the 50's with 6 shot revolvers?
Marksmanship, along with having a round that was lethal at long range helped us win in both World Wars. This line of thinking is now making a resurgence in our military, as a great number of M-14's are being brought out of mothballs, and brought back into service. The demand for them by our soldiers in Afghanistan is very high because of the range potential. These guys are hitting, but not killing with the M-4 at longer ranges. The M-14 in capable hands changes that outcome almost instantly.
These guns all weigh more. That doesn't seem to be of much concern today in Afghanistan as it was 45 years ago in Viet Nam, when Robert McNamara thought the M-16 was the greatest thing to come along since sliced bread in the grocery store. Weight in large caliber firearms is not always such a big deterrent. I don't see anyone trying to market a "light" .50 BMG. There is a reason for that. Bill T.