So the reason the troops in Iraq & so on want a "better rifle" is what exactly? A Rifle is in essence a long range weapon, if it cant do long range its not a good weapon.
That is ironic considering Tucker1371 and I have actually been troops in Iraq and Afghanistan, and the USMC finally adopted the M4 as the general issue rifle for the USMC Infantry last year (replacing the M16A4). It's like you are so tone deaf that you don't realize you are saying, "don't rely on your own experiences in Iraq and Afghanistan! I'll tell you what your opinion should be cause even though you were their your experiences don't support my argument!!!"
At every level of war you want the right mix of capabilities. Every once in a while that right capability is a 7.62x51 rifle that weighs twice as much as an M4 when loaded, and carries half the ammo for weight.
At the strategic level we need things like nukes and stealth bombers and billion dollar aircraft carriers. At the operational level of war we need things like heavy mech brigades and an air operations cell with fighters and tankers and AWACs and drones. And things like air defense artillery with a theater ballistic missile defense system all the way down to Stinger units that it can use to control air corridors.
At the tactical level we need young American men and women without adequate adult supervision to kill the enemy, and those men and women sometimes carry M4s, M16s, M110s, M14s, M107s, M500/M590 shotguns, M249s, M240Bs, AT-4s, Javelins, SMAWs, XM25s (now to be type classified and adopted Army wide), M9s, M11s, MP5s, Mk20s, Mk17s, and sometimes they mount M2s, Mk19s, or use vehicle based cannons like 25mm, 30mm, 105mm, and 120mm. And sometimes they use indirect fire like 60, 81, 120mm mortars, or 105 or 155mm artillery.
In this big selection of available weapon systems, it is important to remember that the right mix of systems is what is important. Having a 30 cal battle rifle won't do you any good when a horde of BMPs starts rolling in on your position. Nor will having a Javelin system do you any good if the enemy is strafing you with a frogfoot.
The M4 is not an ideal weapon because there is no such thing as an ideal weapon. Platonic ideals exist only to allow us to understand that things can be improved. And the M4 can be improved, but the question then becomes "by how much and at what cost?" And we have clearly passed the realm of diminishing returns for replacing the M4. It just isn't cost effective to do so because there isn't anything out there that is worth it. Even then the replacement still won't be ideal.
The Army has been working on lighter weight replacements for the M2, but considering how well they've served, it doesn't make sense to fix what ain't broken.
http://bearingarms.com/world-warcold-wargulf-war-veteran-retire-94-years-service/
Don't get me wrong, there are a lot of things the Army should upgrade, but across the entire "ecosystem" of weapons, I'd pick the TOW and Javelin missiles as more important, the Stryker 30mm upgrade as more important, the BFV 30mm upgrade as more important, the next gen thermal sight (MDS) upgrade for the Apache helicopter as more important, the transition of sniper rifles from 7.62x51 to 300 Win Mag, the acquisition of better, lighter, more secure radios, lighter but stronger body armor and helmets, upgraded armor for our medium trucks, and upgraded field communications for command and staff with LOS redundancy with low probability of intercept antenna designs. Upgrading to something other than the M4 is less needed than almost anything else in the pipeline.
If I had my way, I'd cancel the current pistol trials as well. No point in just getting yet another 9mm when we already have two in the inventory (M9 and M11).
Jimro