Where would this fit in terms of personal weapons?

[Spinward Flow]

Recoil of high velocity weapons can be made to hurt less, but physics says you still take the momentum, and with a heavy projectile like a 30mm grenade that means quite a bit, so it'll still have a hefty recoil.

Cappy addressed this point directly in his reporting:

• Timestamp: 3:50
• Timestamp: 18:07

a low-velocity grenade launcher doesn't need air-burst to be able to hit troops in trenches and defilade - the high arc lets them drop the grenades behind the cover/into the trench.

Is this a nice bit of kit if it works as advertised? Yes. Is it just better than a modern low velocity 40mm? No.

Cappy addressed this point directly in his reporting:

• Timestamp: 5:02
• Timestamp: 6:54

I even found an older video (on a different youtube channel) with a company rep at a public show directly addressing the recoil issue, and how the new design addresses that:

• Timestamp: 1:44

Note that Cappy's video (timestamp 3:50 above) shows a competitor's product which did not win the prize for a go ahead.

 

[Enoki]

Recoil of high velocity weapons can be made to hurt less, but physics says you still take the momentum, and with a heavy projectile like a 30mm grenade that means quite a bit, so it'll still have a hefty recoil.

That depends on velocity far more than mass. If you throwing out HE you don't need a lot of velocity.

As for the laser rangefinder, not using it means you need at least as much skill as with a low velocity 40mm grenade launcher, so there goes that advantage (lower operator skill required). What's more, if you get it wrong, the grenade doesn't miss by a bit and maybe catch someone in the frag radius anyway, it just goes off early or late (and with its high velocity getting it wrong will probably be by enough to hit nothing).

An optical range finder of the sort used in golf today would be sufficient for 500 meters. You don't need pinpoint accuracy with most of the munitions being used.

And don't forget that a 400mm grenade with the same tech (i.e. fuse miniaturisation) can carry more bang. Also, a low-velocity grenade launcher doesn't need air-burst to be able to hit troops in trenches and defilade - the high arc lets them drop the grenades behind the cover/into the trench.

Is this a nice bit of kit if it works as advertised? Yes. Is it just better than a modern low velocity 40mm? No.

But a 4cm grenade is larger and will likely always be heavier than a 3 cm. That extra weight and size per round means fewer carried. The big advantage I see is that you aren't using a compromise weapon in the squad like an M203.

With that you are primarily a rifleman and secondarily a grenadier. Same goes if you are using a rifle grenade attachment on the gun. With something like the 3cm version you carry enough ammo as a squad to allow its use full time. For self-defense you have some shotgun rounds. Losing a bullet tosser rifle isn't going to hurt things.

In Traveller terms, you now have someone that can at least deal to a degree with battle armor and other troops with advanced armor and body protection that you might not be able to with a rifle alone.

 

[aramis]

It's a shotgun with probably 5× the energy density, or a double energy LAG... but with shotshells.
I'd treat it as a 4cm GL, but knocking a die off the damage.

 

[Rupert]

That depends on velocity far more than mass. If you throwing out HE you don't need a lot of velocity.

'Flat trajectory' means 'high velocity'.

An optical range finder of the sort used in golf today would be sufficient for 500 meters. You don't need pinpoint accuracy with most of the munitions being used.

But that's not what's being used...

 

[spank]

Standardization does simplify things a lot,
And quantity has a quality all its own. Having a butt load of something laying around, and a clear need can lead to some interesting innovation, such as the 9mm /stem mag conversations for m3 grease guns.

Or a field expedient method of using 40mm grenades in 60mm mortars.

https://www.reddit.com/r/ForgottenWeapons/s/WrWRCK6VBI

15+ mm and one ounce shells, from memory. Hence one-pounder and two-pounder cannons in the early days of automatic weapons.

One of the problems of small shells is that the fuse can't be smaller than a certain size, so it takes up a greater and greater portion of the available volume as the shell shrinks. 20mm cannon rounds get away with this because 1) the fuse is very simple for such a shell, and 2) they're mainly used for shooting up light vehicles and aircraft and rely on direct hits. An anti-infantry grenade that relies on area effect needs a more sophisticated fuse and more explosive effect, so the minimum useful size of the shell goes up. Vietnam War era 40mm grenades had a tiny explosive charge because the fuse used up so much space. Modern fuses are considerably smaller, and thus a truly modern 40mm grenade will be much more effective than the old ones (and than a high-velocity 30mm grenade that's both smaller and needs to use more mass and volume on the casing to resist firing forces).

That said, I've often thought that the US' dislike of small mortars (despite the really excellent service they got from their 60mm mortars over the years) hasn't done them any favours - a 2"/51mm mortar is man portable and gives more reach and bang than a 40mm grenade launcher (though it is heavier and so is the ammo, of course), and 60mm mortars, while crew served aren't really less portable than GPMGs in sustained fire configuration (and are very easily carried by light vehicles).

One size fits all has gotten any number of defence ministers into trouble.

There is something to be said for one standard model for a specific weapon category, especially if you can't support a multitude of different ones.

That's not to say it doesn't happen, but experience indicates you find one suitable, and bet the farm on it.

 

[casquilho]

And don't forget that a 400mm grenade with the same tech (i.e. fuse miniaturisation) can carry more bang.

I cannot imagine how much recoil a handheld 400mm GL would have.

Yes, I know you mean 40mm but I admit, my brain did a double take when I first read it.

 

[Enoki]

Standardization does simplify things a lot,
And quantity has a quality all its own. Having a butt load of something laying around, and a clear need can lead to some interesting innovation, such as the 9mm /stem mag conversations for m3 grease guns.

Or a field expedient method of using 40mm grenades in 60mm mortars.

https://www.reddit.com/r/ForgottenWeapons/s/WrWRCK6VBI

Or, the old fashioned way...

 

[Condottiere]

Ad hoc mortar.

 

[kilemall]

Ad hoc mortar.

Bit more than that, more precise for shooting through windows for assault work.

 

[Condottiere]

Minor armour piercing, so vehicles aren't off the hook.

I've tried figuring out how this works in the future, and what I keep ending up with is likely engagement range.

You have hand grenades for stuff within throwing range.

Underbarrel grenade launcher for football fields.

And then, the ever popular rocket grenade launcher, at four to eight hundred yards.

 

[Condottiere]

Another aspect is mobility.

You could mount a mortar in the back of a truck, or something smaller, or integrate one into a turret in a modified armoured vehicle.

The difference would be cost, maintenance, and the capability to dismount the mortar.

Also, going by, I think, going by the Swedes, rate of fire.

Man portable, means mobility is that of infantry,