20 x 102mm Phalanx Dummy

I have a 20x102mm Inert round for the Phalanx system. It is a APDS type with white plastic sabot. What is the full designation of this dummy round. The only markings are “INERT” in white and “20MM M103 ACN 91A007-063” in black on the side of the case.

I am out of touch,…but glad to get you the specifics form General Dynamics, who make most of that ammo…must wait a few days


Here’s a little something on it: gd-ots.com/webpdf/20mmMK149.pdf

And this: globalsecurity.org/military/ … /mk149.htm

This I from an ever loyal and resourceful friend in the medium cal world for GDOTS.

He writes

Super cool APDS round and information on it. Amazing how GT-OTS already made over 20 million of those rounds for that gun so far according to the PDF Rick posted the link to. What is the Phalanx gun primarily made to target, incoming missiles?

I have the nose-cone to a target drone that was towed behind a aircraft with a 1 mile long cable. I was told that after the Phalanx disintegrated the drone it was so accurate and devastating that it would shoot up the trailing cable behind the plane being careful not to get to close to the aircraft? It must send allot of rounds down range, fast!

PS: Have fun in Hawaii Pepper!!!

Pepper–If this is not a “Dummy” round, what does the “INERT” refer to. Is this a live round and the projectile is “Inert”.

Note the GREEN one.

And the “stringer” of white tipped ones. The plastic (white) dummies are to the left. Action proving rounds, if you will.

Note the shielded base links. I understand there were issues with EMF/preignition problems when using the electric primered rounds.

A closer look.


I will find out…who knows…could be display and handling items…I will ask…more interesting is to find out about slick rick’s green sabot


In my oppinion a inert round, is a round without propelant, primer-, tracer-, incendiary-, explosives-…mixtures wich can be used for education, instruction or marchandising where the round is used as a sample,
where a loaded round is not nessecary, or prohibitted. A dummy is also an inert round but esspecialy made for training recruts the functioning of the weapens. Wishes Jan.

Awesome Rick, Pepper and Jan. I am not expert, but I like Jan’s explaination / therory.

Rick, those are awesome 25MM rounds. I hope Pepper can find out more on that green one. The links are facinating the way they protect the primer until the last second. I bet that was a design feature designed from a bad learning experience :-)


PS: And how cool is Pepper’s 30MM APFSDS projectile! Is that for a AFV gun?

I want the CIWS desktop model. I’ve got some of the Saddam money. Maybe I can buy it with some Ayatollah currency?!?!?! Get him hooked on numismatics and I’ll hook that brother up! So Pep! Bro! Give me first shot on the CIWS. The time has come to just let it go.


Rick, what is the gun designed for? Does CIWS stand for Close In Weapons System?

Yes. You are correct, SIR! Shipboard anti-pretty much anything, but specifically for flying targets. That’s the gun that requires the “Headstamp Blinders” on the link base. The in-weapon radar apparently generated enough energy to initiate the electric primers. It can be set in autonomous mode, considering some targets are very high-speed and heading in your direction fastly. No “Duh” moment allowed. I understand it is very effective in testing. Not sure if it’s ever been used for real.

I am in line for view the USS Arizona memorial at Pearl Harbor…my GDOTS friends are stumped by the green sabot…but will dig deeper…they had made some black…but D/Ced quick…have taken a bunch of torpedo photos for Jason…Pepper

Thanks for the info Rick!

Can not wait to see the torpedo pics Pepper! Thanks so much for thinking of me in Hawaii! Enjoy the USS Arizona memorial! The bravery of those men are off the charts and impossible to quantify in words.


Nothing really to contribute here, but I really like the pronunciation of CIWS…SEE WHIZ. The stream of fire from a CIWS mount is illustrative of the nick-name.

OK, back to the scholarly discussion.

[quote=“APFSDS”]Thanks for the info Rick!

Can not wait to see the torpedo pics Pepper! Thanks so much for thinking of me in Hawaii! Enjoy the USS Arizona memorial! The bravery of those men are off the charts and impossible to quantify in words.

Well said, I cannot imagine a worse death than being trapped alive inside a ship, hatches jammed shut, with the water rising rapidly around you… I saw the Pearl Harbour movie the other day, things like that really do make you stop and think about it.

Apparently, even today, 67 years later, the Arizona still leaks around a quart of oil per day into the water, which can occasionally be visible on the surface. The surivivors of the Arizona say that the oil will continue to leak until the last survivor dies.

Here’s a link to a video on YouTube of a land-based version of the Phalanx in action:


It seems to be firing HEIT-SD shells rather than DU - you can hear the shells self-destruct a few seconds after each burst is fired. The night shot is especially impressive.

According to some USN crew I’ve heard from, it means “Christ, It Won’t Shoot!”