Mom... Where did you get these?

I guess we’ll probably never know just how many girls working ‘Loading’ at Picatinny Arsenal back around 1944 had their very own collections of WW2 ordnance. Looks like my mom though was one of those girls that did. Sometimes I find myself looking through my late mother’s house just in case there’s maybe another T13 grenade lying around or even just an extra fuze for an M306 57MM RR shell hid away in the dining room buffet or down in the cellar in a box marked “junk.” Well, all I could find today was a box (yes in the buffet) marked “Detonator silver disc and pink discs.” I believe they’re WW2 military ordnance detonator components. Maybe they aren’t, I don’t know. Looks like the “pink discs” dissolved in the same paper towel she wrapped them in back in 1944 or whenever. I assume they were once the explosive component, now degraded into pink stains on the paper towel. Interesting, I thought so anyway.


Possibly they were for the No. 253 fuze for 20MM. Hard to believe that they had to load such small detonators. Dangerous job too. A girl my mom worked with was seriously injured by a detonator.


Here’s a diagram:



Thank you very much for posting the data on the No. 253 Point Detonating Fuze. Now when someone searches the internet they’ll find the info that I couldn’t. They’ll also see how dangerous any live 20MM’s with this fuze are. The fuze I have seems to be an Mk.1 and unfortunately is not a P.A. (it’s a -U-, whoever that was.) I can see now that the cups my mom had, if for this fuze, would have been the relay cups. The “pink disc” I mentioned would likely have been a pink-dyed muslin or other fabric placed between the mercury fulminate and “silver disc” to cushion the crimping process. As you can see, the fuze is an inert specimen (blue). No explosive or live rounds were ever encountered in my mom’s collection.

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BDGreen, where can a get a copy of that manual?


A PDF is available here:

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The brass disc in my fuse has an internal chamfer. Can anyone tell me the correct orientation?


Normally the funnel should face the void. Means if your fuze is oriented with the nose up your disc is correctly oriented as depicted.

Thanks Alex.

What is outer diametr of these “detonators”?

The cups measure 0.190" (4.83mm) O.D. Length of the uncrimped cup is 0.118" (3.01mm.) The I.D. of the No.253 fuze at the point where the relay cup would go is 0.2" (5.09mm), but of course it’s only my speculation that they might have been relays for this fuze. As for the “pink disc”, I’m only guessing that they’re color-coded for mercury fulminate (which I’m told is also pink.)

Seems to me that it could be capsules for old shotgun shells. Red rounds below - shock plates, which were inside capsules. And metall round plates - are clamps for shock plates.
Also some kind of such capsules use also for capsule revolvers.

That’s possible… no way to ask her. I do recall all the stories about her and her father having to bring home all the firearms that my dad would ship home from Europe (during wartime.) His interest though was for a good part machine guns, but did include a lot of others that he bought from the Royal Irish Constabulary. Funny thing is that my brother and I cannot figure out what happened to at least 57 rare WW2-era submachine guns. And just when we decided that he sold them to someone whom we both remember visited frequently around 1960, I find a portion of a wooden stock for an as-of-yet unidentified machine pistol or submachine gun. Now we’re thinking that they’re all either embedded in the concrete of a fall-out shelter or buried in the dam of a farm pond. So it’s possible…

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Hey, just borrow your neighbours ground penetrating radar and take a look around…

Your Mom sounds like she was one cool- and tough- lady!

Ivan, no real connection to any sort of cartridge primer as the detonators here are mainly heat sensitive (I know, I know, there is more to it!) while cartridge primers are laid out for percussion/internal friction.

Badger Jack, we actually did ‘locate’ a Clemson University letter of acknowledgement for a donation of two MG 42 machine guns to that University. But my dad had already told us about that. He also said that one of them was a “really nice” late-model 1944(?) with “sheet metal” cooling… something like that. His roommate was killed in the hedgerows of France, supposedly by this type of gun. He also said he gave Clemson three Maxims. We just don’t know where everything else went. He would never say.

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I see on photo right the same as see every time when have deal with old Russian “ЦБО” capsules. Inscription “DETONATORS” on box does not mean that detonators inside box))) Old one’s ЦБО capsules have one typical feature - shock plates peel off from metal cap of capsules. Right the same way as we see on the photo. Shok plates made with explosive materials shock action. Some of them have red-brown color. Right the same color as on the photo. So, that why my version is believable.

I have experience in assemble cartridges with old shotgun shells and capsules ЦБО. As well as an experience in old capsule rifles and capsule revolvers shooting.

But as any other opinion - it is just one of possible answer. I do not claim that it is final answer.



Ivan, when you look at the images above you will note the items are made of aluminum.
I think we all can agree that these are no “primers” then.

In the US and all western countries (I currently remember) an item designated “detonator” is in no case a primer. Similarity in size shall not misslead anyone.

And normally in Fuzes are hardly any primers are used as we know them from small arms. This is then the part where my experience is coming from (я сапёр).
Besides this I am also a reloader.

It is pitty that you had never see capsules (primers) made of aluminium.
And I think that you had never see all capsules (primers) of all brands and produsers ever.
So, that why your opinion is possible too.

Ivan, you have images of aluminum primers you could show us?
This is very interesting.

My opinion on the item above not being a primer is less basing on the aluminum but more on the knowledge about requirements for detonators in fuzes.
So it might be more of an educated guess than an opinion.