Mills bomb partial detonation

[Nismosonic]

A friend brought this back from Flanders for me, stopped car in a layby for emergency toilet break and picked this up out of ditch, so I assume a number 5, 23 or 36, I've read up many times about mills grenades
only partially exploding due to det cap being offset, I think this must be a great example of this, centre tube blown away
where det exploded, only that side of body is missing, bottom half intact to rear, the grenade Det tube torn and some remains, interestingly the grenade appears to have burst along the external serations. The base plug missing and internal threads torn.
i find this relic piece really interesting, anyone else got any partial detonation examples?
(I have warned him not to touch anything else he may see on his journeys)

Scott.

l

 

[butterfly]

Scott,

thanks for sharing this one. I find bits like this fascinating!

regards Kev

 

[Nismosonic]

Scott,

thanks for sharing this one. I find bits like this fascinating!

regards Kev

Thanks Kev,
Sort of unique, you certainly couldn't plan it that way!

 

[Millsman]

I would not count on this being a partial detonation. There are many field walkers who when they find a Mills, get the club hammer out of their bag, smash the Mills, take the baseplug and leave the bits behind.

The fact that the grenade has split in half is much more likely to have been caused by an external force, be it a club hammer or a plough rather than a detonation. This example clearly lost its plug years ago so it was probably an aluminium plug that has rotted away, then the grenade has been smashed, most likely by farm machinery.

I've always thought there is little evidence of partial or uneven detonation caused by the offset centrepiece. The photo in the Landers book is more likely to be a faulty or part filled detonator, rather than it being offset.

John

 

[SG500]

anyone else got any partial detonation examples?

l

Interesting one Scott. Here's another one but it has been re assembled. The sharp eyed amongst you will realise the striker has fallen down inside the centre tube and there's no spring but you get the general idea that when this one went pop it only did half a job.

Dave.

 

[Anders]

Scott,

thanks for sharing this one. I find bits like this fascinating!

The photo shows fragmentation pieces collected from a single Mills No.36 just after the detonation on soft soil.
The other photo is of two partially detonated No.8. Only the mercury fulminate detonated and failed to set off the secondary explosive.
It was wartime detonators so they have probably been exposed to moisture, or have weakened with time.

I've always thought there is little evidence of partial or uneven detonation caused by the offset centrepiece.

I agree, but there is no doubt in my mind that some kind of detonation has occurred in the detonator tube. The photo clearly indicates that the tube has been split open from the inside.

 

[Nismosonic]

I would not count on this being a partial detonation. There are many field walkers who when they find a Mills, get the club hammer out of their bag, smash the Mills, take the baseplug and leave the bits behind.

The fact that the grenade has split in half is much more likely to have been caused by an external force, be it a club hammer or a plough rather than a detonation. This example clearly lost its plug years ago so it was probably an aluminium plug that has rotted away, then the grenade has been smashed, most likely by farm machinery.

I've always thought there is little evidence of partial or uneven detonation caused by the offset centrepiece. The photo in the Landers book is more likely to be a faulty or part filled detonator, rather than it being offset.

John

As much as I bow down to your superior Knowledge kind sir, I'm convinced the det fired, look at pic 1 and 3..., det tube shredded from what looks like an interior force, and the centre tube has been partially removed/blown away showing the spring underneath, using my dummy det set the area of exposed Spring is level with were cap would have fired, on close inspection, the iron threaded area where base plug was shows signs of brass in some of the thread and some thread completely missing, There is no proof that grenade exploded at all, but in my opinion lots that the detonator fired.

 

[butterfly]

Interesting discussion on this thread.
partial detonation or external damage???

Ok here is my input..... I have copies of documents which show that the SD2 butterfly bomb was extensively tested in relation to explosive effect. The number of fragments were counted and weighed so it was possible to work out the effect and damage inflicted. Of course it is not possible to get results from just one example, a number have to be tested before results can be obtained. If this was done with the butterfly bomb, then I imagine that tests carried out on a British Mills bomb would have been at least ten fold. So does any documentary evidence of such tests survive and if so what do they reveal?
No two detonations would be exactly the same, but by doing these tests an average effect could be found.
Cast iron by nature may carry its own weakneses in its structure, so it would not surprise me to find large pieces of body still intact in a minority of cases.

Going back to Scott's example there has clearly been a detonation within the centre tube (or what remains of it). An internal explosion of the detonator would certainly have effect on the casing, and clearly in this case not the bit that remains. Could a partial detonation cause the case of a mills to 'crack' at the 'weakest' (thinest) point, along the groves of the outer casing? **** I realise that external grooves have no effect on the fragmentation effect of ordnance when they function correctly**** But what happens when they only partially function?

hmmm, over to you guys.

regards Kev

 

[Millsman]

Interesting comments, especially Anders.

I'm pretty sure that any examples of uneven detonation were caused by faulty detonators or mis-filled grenades. Fragmentation tests by William Mills in 1915 didn't show any examples of this problem. However odd examples do crop up but when you think that in a production lifetime of nearly 60 years and perhaps 145 million grenades then there would be the odd anomaly, wouldn't there?

John



John

 

[Millsman]

As much as I bow down to your superior Knowledge kind sir, I'm convinced the det fired, look at pic 1 and 3..., det tube shredded from what looks like an interior force, and the centre tube has been partially removed/blown away showing the spring underneath, using my dummy det set the area of exposed Spring is level with were cap would have fired, on close inspection, the iron threaded area where base plug was shows signs of brass in some of the thread and some thread completely missing, There is no proof that grenade exploded at all, but in my opinion lots that the detonator fired.

I return you to your first post "I've read up many times about mills grenades only partially exploding due to det cap being offset". Being offset does not cause partial detonation. It's a faulty det or a under-filled grenade that will do that. Production faults.

Are the spring and striker still in place in your fragment? All the evidence points to a faulty det which may have popped but not fully detonated and the grenade got broken up at a later date. Without having all the fragments from the same grenade I don't see how you can come to any firm conclusion.

I have seen hundreds of Mills that have been found broken in the field, either by field walkers or farm machinery. The Mills that did the job they were supposed to leave few pieces remaining.

John

 

[oktato]

I'm not sure if it helps the speculation about what happened to that particular Mills, but I thought I would share this photo of the remains of a Mills centre tube where the detonator exploded but failed to set off the main charge. In this case, I can easily imagine the outer casing of the grenade breaking into relatively large segments.

Excuse the quality of the photo and ignore the striker and spring in the background!

Cheers,

Gary

 

[Nismosonic]

In the photo you can clearly see the spring from the striker, also very visible is the shredded det tube. This centre piece is brass so looks different to the zinc examples.
im convinced the det fired, but not that it split the case.

 

[paul the grenade]

Heres a selection of large frags ive picked up over the years at a local gren range used up to the late 50's. some bits ive cleaned up and re varnished. complete undamaged centrepieces turn up every now and then which has often puzzled me. maybe from practice grenades that have shattered after one to many throws.
cheers, Paul.

 

[tiffy]

Hi Guys I regularly walk a WW1 Grenade Training School and have found hundereds of Mills 5 and 23 fragments, they vary from small fragments to the enture first rows of grooves leaving the rifle rod and the "cup" of the botton section just like a candle holder!! Nightlights fit realy well ond look quite seasonal. On 2 ocassions I found grenades with half the side blown out, I presume thease have slipped past quality control and are part charged, instant sectioned grenade. The serrations are to improve grip with muddy hands, not an aid to fragmentation.
Regards and Seasons Greetings.
Tiffy

 

[millsbomber]

Here are a few Examples i have



Took me a while to work out what was going on with this one