Those are the base of the hertz horn linked above, they do not need to be removed only the ampule under the cap, you can unscrew them or remove the priming cup and smash them. The base just holds the ampule and guides the acid into the priming tubes, it’s just a hunk of metal. British WW2 influence triggers are smaller and flatter and so far as I’m aware only the egg shaped mk12(?) ever got anything but hertz horns in coastal use.
The reference video you can actually see that several are bent over already meaning that one is likely a dud which is why they removed the priming cup first rather then the horn first. Essentially they chose to assume they’re already racing the clock and chose rolling it before removing the horns assuming that the broken ones could still leak just enough acid to initiate the ignitor.
Ed: I should point out the hertz horn bases are still in the mine in your reference video, you can see the aluminum hex they’re just harder to see with the extended horn bosses.
Doesn’t that nice video proof that it was not defused? Cap is still on, triggers not screwed out but instead appear broken off?
Those are the base of the hertz horn linked above, they do not need to be removed only the ampule under the cap, you can unscrew them or remove the priming cup and smash them. The base just holds the ampule and guides the acid into the priming tubes, it’s just a hunk of metal. British WW2 influence triggers are smaller and flatter and so far as I’m aware only the egg shaped mk12(?) ever got anything but hertz horns in coastal use.
The reference video you can actually see that several are bent over already meaning that one is likely a dud which is why they removed the priming cup first rather then the horn first. Essentially they chose to assume they’re already racing the clock and chose rolling it before removing the horns assuming that the broken ones could still leak just enough acid to initiate the ignitor.
Defused mk12 with hertz horn bases still in place on display for reference. https://en.m.wikipedia.org/wiki/Mark_XVII_contact_naval_mine#/media/File%3AImperial_War_Museum_North_-_British_Mk_XVII_contact_sea_mine_1.jpg
Ed: I should point out the hertz horn bases are still in the mine in your reference video, you can see the aluminum hex they’re just harder to see with the extended horn bosses.
Super interesting topic. Thanks mate!