Capped Snouts Tin

A capped Snout is an ignition device used in explosive demolitions to set off the larger main charge. These caps were ignited by a detonator and made a small explosion that then set off a much larger explosion when they ignited the primary explosive. In this diagram, the capped snout can be seen fitted to a spring powered pressure detonator:

The explosion the capped snout created was small, but still sufficient to blow a manโ€™s hand off so careful storage and handling was essential and today we are looking at a metal tin that was used to store these capped snouts until they were ready to be used. It is a simple metal box to prevent knocks or sparks setting off the sensitive detonators and it has been painted dark green with black stencilled lettering:

The lettering on the front indicates that the box holds Type VI capped snouts and there is space for a packing date to be added. This example is not dated and came form a seller with a large batch of similarly marked examples leading me to conclude that it was never used and never packed with its intended contents:

Whilst this tin does not have any contents, it is an excellent addition to my small but growing wartime demolitions collection and their use for both clandestine operations and more open engineering projects in the war makes items such as this really interesting to track down for the collection.


  1. I think the ‘capped snout’ simply had a percussion cap fitted and the actual blasting caps were stored separately (definitely better protected than a tin box). The snout gave the user the option of using Bickford fuse to provide a delay – it would be inserted into the ‘snout’ and retained by the spring steel fingers – or a blasting cap that would fit over the ‘snout’ and be crimped in place. (The ‘snout’ existed prior to the MD1 development of Switches 1, 2 & 3, and was initially used with a fuse igniter that was unsuitable for boobytraps (according to Macrae) because it required a lot of force to pull the cotter pin out. Described in Winston Churchill’s Toyshop.)

    • Afterthought: the 1.7 grain detonator was made by ICI and seized on with joy by MD1 as it would reliably fire when pricked by a needle, so they switched to using those instead of the standard percussion caps. (You can see the needle-pointed striker in that drawing of Switch No.2.)

  2. Not a term we used and I don’t recall coming across it in any operational manuals or other texts, but being Canadian we used American and British interchangeably most times.
    We generally referred to such an item as an ‘explosive relay’ or ‘firing train initiator’ or just ‘initiator’.
    That’s the fun thing about military nomenclature, every company with a contract or everyone tasked with writing a manual seems to take it as a challenge coming up with their own ‘official’ wording and strives to make them ever more technically complex, and then there’s the names assigned to them by people who actually use them ๐Ÿ™‚

  3. I’m not familiar with the firing set in the picture but it’s similar to some others I am.
    Looking at it seems to imply that it’s a multi-function set being capable of pressure/pressurerelease/pull/pullrelease and possibly ’tilt rod’ operation depending on how it’s set up. The sharp edge of the ‘mushroom headed pin’ seems to sit in a groove in the striker and either moving it up or across or tilting to disengage or pressing down to fracture the tail of the pre-scored pin could let the spring exercise itself and strike the percussion initiator.
    Now I’ll have to make time to find it in some references and see how it really works, thanks ๐Ÿ™‚

    • I think the drawing is a later version of ‘Switch No.2’, the pressure switch. The silver-steel rod being made deliberately brittle so that pressure on the mushroom head would break it at the groove, though it looks complex enough to be the later ‘universal’ pull, pressure & release switch that was supposed to save needing to carry the three earlier types but the users didn’t like it and stuck with the ones they knew. I used to have a few of the earlier type (and bored out the end cap of a pull switch to take an 8mm blank for use as an alarm mine – which was extremely successful). Didn’t have any ‘Cap Holders’, which I think was the earlier name for the ‘Snouts’, though.

      The earlier devices are shown in “Winston Churchill’s Toyshop” by R.S.Macrae (including drawings)


  4. We weren’t so much concerned with setting IED’s as we were in rendering them safe.
    That said, you have to know how to make one in order to do an RSP and we used to construct them for each other to work on.
    The F1 set was the one normally used for making ‘military style’ training aids, but we preferred to make our own triggers just to add that little level of deviousness and reality to the training, since ones made by ‘amateurs’ are often the hardest to work on and that was not only a challenge but fun too ๐Ÿ™‚
    My favourite was the one I made out of a stack of quarters, the dollar and two dollar coins would have been even better if we’d had themat the time since they’re a lot bigger and there’s more room to work.

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