A new service rifle?

Of course, there will politics as usual.

Every time the topic of replacing the M16 family comes up, the same old bullspit is repeated to justify its replacement.

People bring up flaws in the Stoner gas system (it's not really direct impingement) without mentioning its two main benefits: 1. the recoil impulse is straight back from the chamber.  2. there is a large reduction in mass over a piston system.

Bringing up the flaws about the XM16E1 that have been found and corrected since 1967 just shows you don't really know what you are talking about when discussing replacing the M4.  Just for the record, the powder issue has been settled for decades, you can stop bringing it up like it's germane to the issue at hand.

Pointing out the flaws of the M855 ammunition is valid.  Try to remember when calling it a "varmint" round that 5.56x45mm (M193, M855 and or Mk 262) has successfully killed a whole lot of people over the nearly 50 years of its existence.

What we should be talking about, going forward instead of looking back, is: Can we get a carbine that does everything the M4 does right, without the things it does wrong?

Yes.  There are damn few things so good that there isn't something better out there.

Should we scrap the M4 entire or procure something almost the same?

Yes.  We should clean-slate this.  The magazine alone is the cause of many of the M4's woes; the M16 family's magazine well does not lend itself to fixing that problem.

Once you decide that you're fixing the feed system, you are now free to "fix" the ammo.  Time and again we find that 7mm (or thereabouts) is the ideal infantry caliber.  Time and again we find an excuse to not issue it.  No more excuses, let's adopt the best this time.  I am a fan of the 6.8; but if we're redesigning the mag there's no reason to be constrained by the overall length of the 5.56 round (which 6.8 SPC and 6.5 Grendel both are).

When starting from a clean slate one must decide what the grunts really need.  They do not need a .30 caliber rifle with a 1,000 yard range.  They didn't need that in WW1, and we knew it.  They didn't need it in WW2, but we couldn't afford to scrap the mountains of .30-06 we had.  We don't need it today.  Really!

Infantry action is not target shooting.  Not all grunts are snipers.

We need a round that can effectively kill at around 400m.  That's really all the farther we can tell who we're shooting at.  What this will mean is we will be getting fewer rounds for the same mass.  Everything is a compromise.

There's more to this, but that's all I have for the moment.

h/t Lex