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A couple of Mills Grenade questions

Tim

I've just checked the Naval box that I have and it may have TNT in the stencilling but it is not clear (-NT visible). However each end of the box is stencilled 20/80 which is standard and would not indicate a 'pure' TNT filling.

John
 
John . 80/20 would indicate a filling of Amotal , a mixture often used as the filling for 36's . If memory serves , it has a VOD of some 1000 fps less than TNT so would be an ideal filling for a grenade . Mike .
 
The fillings for the 36M from 1917 onward were Trotyl (i.e. TNT), Baratol and Cilferite "C". The latter filling reacted with the aluminium centre pieces and in September 1932 it was advised to destroy all 36 grenades filled Cilferite "C", leaving only those filled TNT and Baratol. In November 1932 Cilferite "C" was declared obsolete for all future grenade filling, but so also was TNT.

Thus Baratol became the preferred Land Service filling for grenades, a ratio 20% Ba nitrate to 80% TNT being the standard. Consideration was given to using 40% and 70% Ba nitrate in order to conserve TNT in wartime, but 20/80 gave good performance and did not "cake" when stored at elevated temperatures - note attached. Another advantage of Baratol was that the purity of the TNT used could be Grade II, which reduced the manufacturing cost and time to produce it. However, for a number of reasons to do with performance and increased guarantee of supply, Grade I crystalline or flaked TNT was used as an alternative No.36 filling during WWII.

The photo shows boxes marked as containing Baratol filled No.36, with 4s Mk7 igniters (not the 3s MkIV used in the Holman Projector). As for the "For Naval Use Only" stamp, it is probably simply no more than the Navy inspectors marking their property - on what might otherwise be seen as a Land Service store - and emphasising it has been issued to a Naval contract.




Tom.
 

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Tom Thanks for that info , I'd never have thought grade 1 TNT was a suitable filling for a grenade but , obviously , I must be mistaken . Did pure TNT grenades have different markings ? Usually , any different fillings would be indicated in some way on British ordnance . Mike.
 
Mike,

Way back in December 1916 when Grenades No.23 MkII for Mesopotamia were first being discussed, the very first filling was "70 grams of Trotyl crystals No.1 grade". For interest is attached one of the early memos.

As for distinguishing the actual explosive, it wasn't that explicit on the grenades, perhaps because there was not the physical space. A green band denoted both Trotyl (TNT) and Baratol on "M" grenades, while it also denoted Amatol 80/20 (or 83/17) on Non-M. The transit boxes tended to indicate the exact fillings, as in the previous photo of WWII era boxes - the marking "20/80" defines 20:80 Baratol.

I believe it was larger ordnance such as aerial bombs, mortar bombs, torpedoes and artillery shells that had the actual type of explosive stencilled onto the bodies.



Tom.
 

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The drawing attached gives the impression that the Trotyl is the 20% to 80% Baratol.

Which is the correct way round?

John

No36.jpg
 
The drawing attached gives the impression that the Trotyl is the 20% to 80% Baratol.

Which is the correct way round?

John

John,

The protocol is that the first figure is the percentage of the salt, the second figure the percentage of TNT.

The drawing is perfectly correct, or at least I can't see anything astray. Baratol 20/80 indicates barium nitrate at 20% and TNT at 80%. For the Amatols, Amatol 80/20 is 80% ammonium nitrate and TNT 20%; I leave you to work out the Amatol 83/17...




Tom.
 
Sorry Tom

Two questions:-

I'm not familiar with this use of 'salt'. Is it as an accelerant / stabiliser or what?

It Tim's 1927 book wrong to state there were Navy 36's with 100% TNT ?

John
 
John . Salt is the commonly used chemical description of any other chemical that has been combined with an acid to form a new compound . IE Amatol is TNT mixed with ammonium nitrate which is explosive in its own right in certain circumstances . Ammonium nitrate is made by mixing nitric acid with an ammonium based compound , usually ammonium hydroxide . The point of mixing the HE TNT with the LE ammonium nitrate [or barium nitrate in the case of Baratol] is to alter the explosive properties of the resultant product , usually a lower VOD but also a cost saving measure as the salts used are massively cheaper to produce than TNT . Mike
 
I'm not familiar with this use of 'salt'. Is it as an accelerant / stabiliser or what?

It Tim's 1927 book wrong to state there were Navy 36's with 100% TNT ?John

Here salt is just the generic term for the nitric acid salts of first barium and then ammonia. ("Common" salt, or sodium chloride, is of course the hydrochloric acid salt of sodium.) The salts are modifiers; rather than take the thread totally off track I will PM you.

Up until 1932-33 Trotyl (or TNT) was a standard 36M filling, so there is no reason why the Navy shouldn't have had such in the 1920s.



Tom.
 
Many thanks to Mike and Tom for their explanations (and Tom's fuller PM). My Chemistry didn't go past 'O' Level and the syllabus didn't cover high explosives.

John
 
Old age creeping in again . I'd TOTALLY forgotten that Trotyl was sometimes used as a grenade filling . It would be interesting to see the results of the explosion tests between a Mills filled with Trotyl & one filled with Baratol . I would think that the Trotyl one would be a truly fearsome creature !
 
Thank you to all who have contributed on this. My original questions have been answered In some detail, and I have learned something else along the way too. Tony.
 
On the face of it the Mills appears a simple product. Under the surface is a deep, complex and fascinating story of development, trials, errors and successes. It seems possible to learn something every day.

John
 
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