Should the 5.56 Nato round be replaced after this conflict?

1LT William Clardy - The conversion from the A1 to the A2 isn't really a good example to use because the A2s (and all subsequent iterations) are fully backwards compatible with the old M193 ammo used in by the A1s. So if you, by some happenstance, were issued old M193 ball for your M4 carbine, you'd be able to shoot it just fine (after you re-zero to take account for the POA/POI shift with the lighter round). In that scenario, you could use up all the old ammo stocks while moving to the newer round, thus those rounds would not go to waste. With a caliber change, you couldn't do that.

LTC Paul Labrador, I was referencing the conversion from A1 to A2 as an instance where at least part of the cost of the conversion was at least partially offset by it being done in lieu of already-needed maintenance -- e.g., all those M16A1s (and probably even the M16E1 I was assigned when I was with the 101st) which still had the same barrel they came back from Vietnam with, so the effective cost of the barrel component of the A2 upgrade was really just the delta between what it would have cost to replace all those A1 barrels with new A1 barrels and replacing them with the A2's slightly heavier barrel.

I would also note that the current standard 5.56x45mm ammunition is a truly perverse (at least from a logistician's perspective) combination of being expensive to manufacture as well as being extremely harsh on the weapons. So there are some very valid argument to be made for moving away from it from which make sense even from a strictly cost-effectiveness point of view.

1LT William Clardy - Yes, the upgrade was rolled into the cost of weapon upkeep, but because they didn't change caliber, as I stated, you didn't run into the cost of having to waste already manufactured ammunition, or change out any other parts that would have occurred with a caliber change (magazines, bolts, cleaning equipment, etc). Those costs add up too.

I'm not denying that those other costs add up, LTC Paul Labrador, I'm just trying to remind anybody paying attention that some of the costs are going to happen anyway, and that there is a possibility that a change could reduce some of the recurring costs (assuming we aren't typically American and make the new ammo just as expensively exotic, just to prove we can).

LTC Paul Labrador - Furthermore any conflict we enter makes it to where signatories to the Hague can ignore the conventions, by our very presence. What's worse is that with rifle rounds the tail of the bullet "may" be more important that the tip on some rounds, which HAS falsely classified some of our 7.62 as "hollowpoint" incorrectly.

Sgt Aaron Kennedy, MS - Correct. If you want a projectile to yaw consistently and violently upon impact, you need the tail to be where the center of gravity is. With bullets like that, it wants to go tail first as soon as it hits anything denser than air.

Moving the center of gravity too far aft reduces the hit probability (or at least the consistency of trajectory), LTC Paul Labrador. For inducing bullet yaw on impact, I thought the Russians produced a typically straightforward technical solution with the shallow asymmetrical cup on the nose of their 5.45mm round -- the cup produces a sideways force on impact, but the bullet's center of mass is still closely aligned with the axis of the bullet (in other words, it still spins smoothly with no erratic wobble).

SSG Jason Werstak - That's one specific round where that works, on a Non-Nato round. It affects our supply chain. 2nd order effects. It's great to believe that we can swap out the barrels of 1M~ rifles and that is the only issue. It isn't.

PV2 Aaron Bennett, SPC Christopher Morehouse is also overlooking the fact that the bullet almost always contributes more to the total weight of a round than the cartridge case. Yet another reason why caseless ammunition has generally proved to add more problems than it solves.

PV2 Aaron Bennett - One of many problems that need to be overcome. But there is no pay off for the military switching from the 5.56 without aome generational leap in capability. So if it takes another 30 years to make it work, that will be how long we stick with the 5.56

1LT William Clardy - Actually a brass 556 NATO casing weighs between 185 and 200 grain, vs a 63 grain bullet. In 2012 the army had a request from vendors for an alternative casing design to cut its weight by 10%.

SPC Christopher Morehouse, I'll have to cede you that point -- I was thinking more about pistol and full-power rifle rounds, where the bullet tends to be a much bigger portion of the round's mass.

Except in the last 15 years CSM for Combat Missions through OIF and OEF

No, it's not. 5.56 has put piles of bad guys in the ground. Much of the criticism coming out of Theater has been antidotal and is based on exactly what I stated.

Are there calibers that offer increased range and terminal performance? Yes, but they come at a price. Weight, recoil, and platform to start, but there are other costs across the DTMLPF domains that must be considered.

An AR10 lower is considerably larger than a standard AR15/M4 lower. 308 uppers are NOT compatible with 5.56 variant lowers.

That's not really true. Everything is different except the pistol grip and trigger group. Both receivers are larger. Even the buffer and buffer spring are larger and heavier.