I had assumed that typical HE rounds were most effective against entrenched infantry. But then I am no artillery expert. I yield to your superior knowledge.
First, here's an absolutely fantastic article from last September by a former U.S. army artillery officer advocating we send DPICM rounds to Ukraine, and explaining why they are so valuable. He's dead-on, and what he's saying would not be the least bit controversial among artillery professionals.
They may indeed be a game-changer in an artillery-heavy war like this one. And that's not an exaggeration. I think a lot of people who don't understand how devastating those rounds are underestimate their impact. They're not glamorous, but they are incredibly effective.
https://smallwarsjournal.com/jrnl/art/give-ukraine-right-artillery-ammo-dpicmTo answer your point, traditional HE rounds with a point-detonating ("PD) fuze are very
ineffective against troops in trenches, basically requiring a direct hit. Rounds to which a variable-time ("VT") fuze that causes them to explode a certain distance above the ground (usually between 20-30 feet) are perhaps 3 times more effective because the angle of the burst allows some fragments to enter trenches 20-30 meters out from the point on the ground over which the fuze detonates. That's just a matter of screwing a different fuze on the round prior to firing. However, we don't have nearly as many VT fuzes as we have HE rounds, and my guess is that we stopped sending VT fuzes to Ukraine a long time ago. So, they've likely been using just straight point detonating.
DPICM rounds, though, contain either 72 or 88 bomblets (the version with 72 bomblets is newer, with fewer duds), each essentially the equivalent of a grenade, and they'll spread out over about a 150 meter radius. A single 6 gun battery firing just one round puts 432 bomblets in the impact area. Ouch. They are many times more effective even than VT.
Important to note also that DPICM those were our
default rounds. They're force-multipliers that mean you can transport the same combat power in far fewer rounds. So that's less wear and tear on the tubes, far fewer guns are required, and you can deliver a heavy combat punch more more quickly and then displace, making you much less vulnerable to counter-battery fire.
The only non-DPICM rounds my battery fired in the Gulf War were long-range rocket assisted rounds that don't come in a DPICM version. We didn't fire a single point-denoting or VT HE round the entire war -- DPICM are that much more effective. They are/were our standard round, and the majority of the ammunition we produced. That also means that because we haven't been sending them, we have millions still in reserve. So even if they weren't far superior to HE rounds, they're sort of all we have left to spare.
To give a quick "war-story", my 8-gun battery got a fire mission targeting an Iraqi infantry battalion in the open. Roughly 400-500 troops, and I directed DPICM. We fired just
two volleys (16 rounds, 1408 submunitions), and were told to "cease fire". Mass hands-up surrender. Now, that was in the desert which is going to maximize effectiveness against troops in the open. Still, the grunts I talk to later said it was like the entire ground for hundreds of meters just exploded. They were kind of in awe of it. So the damn rounds are definitely effective.
If the rounds are more effective, then just send them. Don't make some big announcement about it (followed by two more at later dates) before getting around to actually supplying them to Ukraine.
Well, a legal waiver by the President was required to export them, so there really wasn't a way to keep it quiet. It's been a rather hotly debated topic almost since the war began for people who follow such things, and there was no way the media or opponents of sending them would have kept it quiet. Better to do it openly rather than try to sneak it through and have it exposed anyway. However, Biden did screw-up big time by saying publicly that our stockpiles of non-DPICM ammunition were "low".
ETA:I realize in rereading this post that it sounds rather over-the-top and geeky, but hey, it isn't very often that acquired knowledge of artillery rounds has much relevance to any discussion anyway. lol.
