stancrist said:

Good questions.  Unfortunately, I've never come across  that info.

A long time ago some reservists from my old job got to fire 40 rounds at a M113 hulk. It drills a neat 6 mm hole though the armour but behind armour effect seemed pretty minor. 

Stancrist

"HEDP was opted for in order to have one ammo type that could be used against both personnel and light armored vehicles.

HE is ineffective against light armor, so grenadiers would have to carry reduced amounts of two ammo types:  HE and HEAT."

A well designed HE fragmentation is much more effective against personnel. How often are grenadiers taking pot shots at light armored vehicles vs shooting at enemy personnel? Most missions aren't defending the Fulda Gap in 1980 against hordes of Soviet tanks and BMPs.

They could carry a few HEDP for when needed. In most cases for current missions a good HE would be useful. 

Loadouts can be tailored for the current mission.

I fully agree.  The decision to go HEDP was a post-Vietnam War decision, when defending against invading Russian BMPs dominated planning.  I'd guess they stayed with HEDP because of institutional inertia.

However, they did elect to go with an optimized HE-fragmentation round for the XM25, and apparently intend to do likewise with the proposed new weapon system.

Red7272 said:

A long time ago some reservists from my old job got to fire 40 rounds at a M113 hulk. It drills a neat 6 mm hole though the armour but behind armour effect seemed pretty minor.

Yes, even with larger shaped charges like the RPG, the behind armor effect is reportedly minor, unless fuel, explosives, or personnel are in the direct path of the jet.

stancrist said:

Yes, even with larger shaped charges like the RPG, the behind armor effect is reportedly minor, unless fuel, explosives, or personnel are in the direct path of the jet.

To be expected. I'm not sure if any other NATO country uses HEAT 40 mm. Certainly the Germans went for a much more effective HE with a superior fuse when they adopted the grenade launcher. 

Blowhard personality aside, here's at least decent footage of HEDP impacts (see around 4:42 and 7:18)

https://youtu.be/oqyLoU_0Av4?t=282

It sucks. At least 40x53 has a beefy enough steel body that it gives you decent fragmentation along with the pencil diameter hole it punches if you really MUST go HEDP, and putting that projectile into a lower pressure / velocity casing has been proposed in the past.

We're not fighting BMPs and even if we were we're equipped for near peer conflicts with enemy armored divisions. We have no shortage of things that can kill armor.   What we really need is a dedicated MV HE round, with a bounding function, plus incorporation of advances in fuze miniaturization since the stone age, then improved fillers, projectile design, and PFF / fragmentation optimization so you can eek every last bit of performance out of the little guy.

It's all been thoroughly studied and would be a pretty straightforward procurement, but it's kind of like hem and hawing over what pistol to buy -- those making these decisions don't think it matters much in the grand scheme of things, the war isn't going to be won or lost over it (though someone's life might, that's outside their scope of consideration).

We're reaching a point now where you can probably come up with a drone that fits in a 40mm grenade pouch that can reach out beyond 1,000m... and even if the tradeoff is a payload more like a 20mm or 25mm projectile, it ain't gonna matter when you deliver it into their lap.  Probably not going to get away with it in a near peer conflict with heavy EW, but for anything less you might as well get into the game because the enemy certainly will.

Refleks said:

We're reaching a point now where you can probably come up with a drone that fits in a 40mm grenade pouch that can reach out beyond 1,000m... and even if the tradeoff is a payload more like a 20mm or 25mm projectile,

https://soldiersystems.net/2019/05/24/sofic-19-defendtex-drone-40/

The round is fired from the launcher in order to get it aloft. To attain flight mode, it deploys four helicopter-style rotors to stabilize, move, and provide lift for loiter.

It offers 12 minutes of flight time and/or 20 minutes of loiter time. Cruising speed is 20 m/s and range at optimum speed is in excess of 10km.

Payloads include camera, anti-armor, fuel-air, HE/frag, diversionary, smoke, counter-UAS,

Red7272 said:

To be expected. I'm not sure if any other NATO country uses HEAT 40 mm. Certainly the Germans went for a much more effective HE with a superior fuse when they adopted the grenade launcher.

France bought 40 mm HEDP grenades to go with the HK269 F launcher... but we are also using rifle grenades (but don't repeat it, it's a secret!)

EmericD said:

France bought 40 mm HEDP grenades to go with the HK269 F launcher... but we are also using rifle grenades (but don't repeat it, it's a secret!)

How is this expected to work out in practice, Emeric? Will some units have the UBGLs and others the RGs? Or will the 40mm eventually take over?

Some nice pics of experimental US grenade rounds in this thread: https://forum.cartridgecollectors.org/t/grenade-launcher-cartridges/41601

All units will have HK269 F (probably one per fireteam) and riflemen without the 40 mm GL could use rifle grenades instead.