schnuersi said:

Yes and that includes over 100 m.

Of course.  My point is there was no base assumption that "the rifleman contributes in a significant way to the firepower for firefights above 100 m".

Just the opposite.  They knew the rifleman's contribution to fights above 100 meters was not significant.  OICW sought to improve his effectiveness.

schnuersi said:

It resulted in a compromise that ultimately made the system ineffective. They made the HE component flat shooting with a small grenade.

Yes.  They tried to do too much with too little.

schnuersi said:

But what you actually want is an arcing trajectory and a large grenade.

Concur on the need for a large grenade, but I see no need for an arcing trajectory with airburst rounds.  Indeed, I think that in most infantry vs infantry combat scenarios, a flat trajectory would be preferable with airburst munitions.

stancrist said:

Which is why I think it necessary to go significantly bigger than 25mm.

What was the grenade caliber selected for OICW? Significantly bigger than 25 mm?

stancrist said:

Not true. While 9 grenades were thrown, 8 were thrown with insufficient accuracy, and exploded harmlessly.

I see, so when you are missing your target, ammo consumption does not count and the grenades are automatically respawning in your grenade pouches?

That would be a nice mod for call of duty.

stancrist said:

That might be true for airbursts above soldiers in a trench, but airbursts above soldiers who are standing, kneeling, or lying prone could be hit in the arms, lower torso, legs, or feet. BTW, in what army is it SOP for infantry to have shoulder armor?

The area of a sphere is 4.Pi.r², or 12.6 m² at a 1 m distance from the grenade, 50.3 m² at a distance of 2 m, and 113 m² at a distance of 3 m.

The standard crouching soldier target is ~0.38 m², so you need a fragment density of 2.63 frags/m² to expect scoring a hit on this target.

That means that you need at least 33 effective fragments to score a hit at 1 m, 132 effective fragments to score a hit a 2 m, and 297 effective fragments to score a hit at 3 m, on any random part of this target.

How many fragments of 1 gram could be loaded in a 40 mm / 180 g HE grenade?

And if shoulder armor is not currently standard practice, most armies have already this kind of protection in their inventories.

One factor which hasn't been mentioned recently: suppression.

From what I recall of suppression effectiveness research, a 40mm grenade exploding in the general vicinity has a vastly greater suppressive effect than any small arms bullets.

stancrist said:

OICW sought to improve his effectiveness.

Yes and that was dumb. If the effectiveness is 0,01 and I double it it becomes 0,02. Which is such a marginal improvement it is hardly worth any resource invenstment.
The effectiveness of a rifleman or better infantry man goes up significantly from 100 m and closer. So doubling a significantly larger number would have yielded significant results... most likely for less resource investment.

stancrist said:

but I see no need for an arcing trajectory with airburst rounds. Indeed, I think that in most infantry vs infantry combat scenarios, a flat trajectory would be preferable with airburst munitions.

Why? The rifle/small arm has a flat trajectory. Why have two weapons with the same profile?
For engaging targets behind cover or in defilade an arcing trajectory is far better. If airburst is used all the better. The fragmentation pattern of a steep falling grenade bursting 2 m above ground is far better and more efficient than that of a grenade traveling allmost parallel to  the ground.
Simple air burst fuses (proximity) for rifle grenades for example would work great. This solution would be dirt cheap in comparison and offer a significant improvement. Issue such grenades liberally to you men and an infantry squad can fire an instant light mortar barrage while the machine gunner supresses and pins the enemy.

autogun said:

From what I recall of suppression effectiveness research, a 40mm grenade exploding in the general vicinity has a vastly greater suppressive effect than any small arms bullets.

Yes but it there is a time aspect to supression. So to keep the effect up there needs to be repeated impacts. The question is how this effect scales. Since 40 mm grenades are rather large and heavy.

stancrist said:

Concur on the need for a large grenade, but I see no need for an arcing trajectory with airburst rounds.

Keeping recoil to a safe level?

A large grenade launched at high MV (to have a flat trajectory) will have too much recoil for being shoulder-launched.

The 40x53 mm is already producing too much recoil for a shoulder-fire system, and it's not really a "large" grenade (but the MV is OK).

Additionnally, with a high-velocity grenade you need to setup the fuze after firing, because you need to take into account the round-to-round velocity dispersion, or the grenade will detonate either too short or too long.

EmericD said:

How many fragments of 1 gram could be loaded in a 40 mm / 180 g HE grenade?

STK used 330x 0.25g Tungsten balls in its LVER grenade concept:

https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2005/smallarms/thursday/fong.pdf

Performance as described - even against IIIA type protection - looks pretty solid.

It's basically like a micro claymore mine. 

gatnerd said:

STK used 330x 0.25g Tungsten balls in its LVER grenade concept:

So that is 82 g of W per grenade... in this case I think W core AP bullets are the better choice. As long as only a few of these grenades are used the use of W may be fine but since the idea we are talking about is wide spread distribution and mass use I think there is a problem here.

Furthermore 1,6 mm Ti plus 20 layers of Kevlar is CRISAT. STANAG 4512 does not define protection levels but targets for testing. So it can not be assumed that these fragments will penetrate Lvl 3A which is significantly better than CRISAT. Steel fragments will perform even worse.
0,25 g fragments also will loose KE fast. While the cloud is nice and dense the effective radius is lowish.
Its also easy to see that the vast majority of fragments is projected forward. This would work great in an arcing trajectory with time or proximity fuse so the main mass of the fragments is projected forward and down onto the target. If the trajectory gets more parallel to the ground and airburst is used only a few fragments will be projected downwards and downwards forward onto targets in defilade or cover. The majority will be projected forward in direction of the shot and some more upward and to the sides. All of which are ineffective.

The Chicoms are doing a ton of extremely interesting work with their "sniper grenade launchers"

They even ran the velocity up to 325-350 meters per second at one point to see if it made them more capable.

Needless to say recoil was an issue lol.

This said, I believe there's a workable way around this.

So I'm going to avoid writing a detailed point by point response for the sake of brevity and because I can say this quickly.

There's some other things we see in Ukraine which is what I was trying to point your attention to with my previous post, which you kinda missed the point of sadly.

This other thing we see in Ukraine is Ukrainian SOF absolutely WRECKING Russian units at night because the ukies sof is extremely well supplied with quad tubes and thermals and can see the Russians at ranges where the Russians don't even know they're near them!

When you couple things like an SSW with ubiquitous thermals and other enablers you genuinely can wreck an enemy formation without them seeing you until it's too late putting you at minimal risk.

I agree with your larger points on the Ukraine war meta but we're discussing infantry combat and blowing off organic capability to do things like this by blithely saying why not use a mortar is not helpful or useful.

Stuff like this gives you the ability to do these things if you don't have arty cover or allows your arty cover to prioritize more important stuff, both of which are useful.