I trained on the M14 in the Navy. I owned an M1 Garand.
That's why I now have an FN FAL. Both M14 and M1 are second rate compared to it. Most of NATO used the FN FAL while we stuck to the M14 for what must be political reasons. My A.R.M.S. scope mount slides in and out of the upper receiver without any securing screws, holds zero, and returns to zero after dismounting and remounting. You can swap mount and scope in seconds and have zero concerns about a scope mount screw coming loose....because there aren't any (scope rings could have a screw loose, but it has never happened since 1994). My rifle shoots 1 MOA in pure stock configuration, except for the thumbhole Bell & Carlson stock Springfield Armory equipped them with. The flash suppressor was also left off to comply with import restrictions back in the early 90's. Sold as the SAR 4800 back then. For about $1000.
But back to the original intent of the thread. There is no use concerning yourself about changing the current issue rifles until the defense department decides to correct an earlier and far more basic problem with the ammo. A big mistake was made when small bore rifles adopted a breech locking system similar to large bore artillery pieces. Head spacing is a critical issue with the current system, and the bolt must be locked into the receiver before a round can be safely fired.
The Oerlikon autocannon solved both problems by used a rebated bolt that fit INTO the cartridge base, not over the cartridge base. The round could be shoved far into the chamber, with the bolt following it, far beyond the rear boundary of the chamber. There was no bolt lockup, because it was a simple blowback system. By the time the straightsided cartridge case extended beyond the rear of the chamber, the bullet was long gone and case pressure was far below maximum safe levels. There is zero headspacing problem, as the bolt shoves the cartridge to the front of the bore before firing. Look up the Oerlikon autocannon and see a good idea that was mostly wasted.
The proposed M/2030 round gives a choice of a small caliber, high speed sabot bullet and a large caliber, medium speed bullet out of the same barrel. Ammo can be suited to the task at hand, without changing barrels on a rifle or having to carry two different rifles. Give the M/2030 round a rebated case head and use a suitable bolt in a simple blowback system, and you have a new class of more reliable, more cost effective, easier to maintain, and more effective battle rifle. Don't expect it to happen very soon. The military is dogmatic and there are stockpiles of 5.56 and 7.62 NATO ammo needing to be used up, and lots of infrastructure to manufacture those rounds that is not worn out yet. Optical sights are not standard issue on all U.S. battle rifles, and that is a situation that is DECADES behind the times. Also, lack of suppressors to preserve hearing which can be critical in combat, not to mention future personal problems, is also many decades behind the times.
Defense Department is full of idiots (or more probably just self serving individuals who consider their position ahead of other considerations and you consider them idiots because of it), and what the common soldier has compared to what he could have in the way of a better rifle is only one proof of that.
The REAL solution to the problem is to grab the sons of the Puppetmasters and throw THEM into uniforms and let THEM get killed for the sake of Empire Amerika. All of a sudden, state-of-the-art weaponry would start showing up, as their sons would probably count for something to them. Your sons do NOT count for much of anything to them. Never have. Read some history books.
But also consider that a battle rifle means diddly squat compared to a Minuteman 3 or Trident nuclear intercontinental ballistic missile......or a stealth bomber or fighter. In event of a nuclear war, the main use of a battle rifle would be in its own country of origin controlling the civilian population.
How good of a battle rifle do you want controlling YOU if such an event occurs??? If such an event does not occur, history will keep repeating itself where soldiers die for the sake of those who use them for their own ends. Some things are more important to consider than how good is the basic weaponry of the conscripts.
If you want a good rifle, buy your own, and quit expecting somebody to give you one. For most of history, officers in charge of conscripts did just that. As Solomon said, there is nothing new under the sun.