A couple of points about primers:

Not all aircraft guns use electric priming: the GAU-12/U (AV-8B) and GAU-22/A (F-35) fire NATO 25 x 137 ammo which uses percussion priming. The GAU-8/A (A-10 aircraft and Goalkeeper CIWS) uses percussion-primed 30 x 173 NATO.

The US has developed a percussion-primed version of the M230 Chain Gun for naval use (30 x 113B ammo), but I don't think it has any takers so far.

Interestingly, Nexter makes two versions of the 30M550 series cannon in 30 x 113B, differing in the characteristics of the electric priming (one being relatively insensitive, intended mainly for use by naval aircraft). The 30M791 (30 x 150B in Rafale) also has the insensitive priming.

Yes, the USN does take precautions in handling the electric-primed 20 x 102 ammo for the Phalanx system. When it is in the magazine, the base of the ammo, containing the primer, is protected from electrical interference.

Looks like .ru used 122 mm flechette rounds against civilians in Bucha

https://www.theguardian.com/world/2022/apr/24/dozens-bucha-civilians-killed-flechettes-metal-darts-russian-artillery

Take it with a grain of salt with all the propaganda being published. So it was either Russians shelling themselves while in Bucha or Ukrainians shelling the Russians while they occupied in Bucha? Which sounds more likely? Both sides are using more or less the same artillery types and ordanance.

But even more amusing is a claim in another article that says flechettes are practically unseen in modern conflict.

https://www.economist.com/the-economist-explains/2022/04/24/what-are-flechettes-a-brutal-weapon-used-in-ukraine

https://www.washingtonpost.com/world/2022/04/18/flechette-projectile-ukraine-russia/?utm_source=feedly

schnuersi said:

So from my point of view there are two possibilities. Either the safety meansures are way to cautios and interfere with the sensible operation of the system or the ammo for Phalanx is more sensitive than others and this would be a flaw.

Third option: your typical modern boat is radiating much more power than a tank or a plane, and once the ammo is in the Phalanx magazine the primer is shielded from HERO, so it's no longer a problem.

EmericD said:

Third option: your typical modern boat is radiating much more power than a tank or a plane, and once the ammo is in the Phalanx magazine the primer is shielded from HERO, so it's no longer a problem.

Sorry but to me this is a design flaw. Phalanx, the gun the system uses and the ammo are not new. The system has been in use for decades.
IF the primer is that sensitive they should have replaced it decades ago by one that is safe to handle. With all the focus on safety. Insensitive ammo etc the solution for handling 20 mm ammo of a legacy design that is not up to modern standards is to basically turn the ship off?

Officially in the German army its forbidden to handle 120 mm ammo while wearing gloves. Because these could generate a static charge that might set off the primer... but this is toroughly ignored. Everybody handles the ammo with gloves. All the time. Nothing ever happend. During my service time it was forbidden to use cell phones when handling 120 mm ammo. But having it in a pocket was ok. As was using radios. This was back in the days when it was forbidden to use a cell phone at the gas station because people feared it might set off the fuel.
IF these old primers for the 20 mm ammo are really that sensitive that they will go off and its not just a posibility that is not zero and thus could be safely ignored IMHO there is no excuse for not immediatly replacing these primers because of safety concerns.

Another new one. Polish loitering munition WARMATE now being used:

Twitter

Ukraine Weapons Tracker on Twitter

#Ukraine: The first appearance of the Polish WARMATE loitering munition armed with a HE-FRAG warhead being used by... https://t.co/zHbC8AFaR0

Read more from Twitter

https://www.wbgroup.pl/en/produkt/warmate-loitering-munnitions/

Mine clearing charge used against a building:

Twitter

OSINTtechnical on Twitter

Russian UR-77 Meteorit mine-clearing line charge launcher used against a target in Rubizhne. A tactic we have seen... https://t.co/5fQd59DAlZ

Read more from Twitter

Fagot ATGM mounted on an off road golf cart as a 'micro technical' 

Twitter

C?????? O?s???? on Twitter

Ukrainian SOF firing a buggy-mounted 9M111 Fagot ATGM https://t.co/lmfBHNIGmu

Read more from Twitter

schnuersi said:

Sorry but to me this is a design flaw. Phalanx, the gun the system uses and the ammo are not new. The system has been in use for decades. IF the primer is that sensitive they should have replaced it decades ago by one that is safe to handle. With all the focus on safety. Insensitive ammo etc the solution for handling 20 mm ammo of a legacy design that is not up to modern standards is to basically turn the ship off?

In the early 1990s they did actually do work on an insensitive primer for the CIWS ammo.  

https://apps.dtic.mil/sti/pdfs/ADA514389.pdf

It's not totally clear this was adopted, but it was mentioned in the FY93 Congressional budget discussions, so I suspect it actually was.  Which suggests that if the safety precautions are still in effect, It may be an abundance of caution issue rather than a definite need.

SMFH.

HERO is not only regarding 20x102, it’s for all ordnance.

There are also personnel exclusion zones surrounding antennae on warships, to prevent injuries to people from high power RF emissions.

Also, EMCON is a thing, so “turn the ship off” is a silly way to look at it.

Your frame of reference is too limited to claim poor design.