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57x307R steel shell 'cut away'.


Well-Known Member
57x307R steel shell 'cutaway'.

This may be a little off topic but its the only 'cutaway' I have.

The result of 4 grames of F.G. powder going bang.


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The theory was -

That this like the smaller 37mm & 47mm versions weren't meant to actually blow up anything. They were supposed to penetrate and then explode creating a spray of fast moving fragments that caused the damage. This is why there are so few solid shot found in these small calibers at this time (Pre WW1) they created only one hole in a limited area even though they could penetrate further,so were not considered useful and not made in any quantity. (a cheaper projectile to make for practice however)


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Black powder being a low explosive tends to break a projectile into a small number of large fragments rather than the large number of small fragments produced by high explosve shells.
The steel shell was designed, as Gspragge states, to pierce the target and then detonate behind the armour.
I wonder what the AP performance of the round was? The 6-PR 6 CWT Mk II was used as an A/T gun in home defence during 1940.
I'd guess that at short range they may have been able to pierce the armour of German tanks of the period? (the frontal armour of the PZ III was only 30mm at the time).

Hi Quatermass,
Thats an interesting piece to have, i have in the past looked at the size of the cavity that the charge would have sat in and wondered just how much of a bang it would make, as it is not a very large space compared to the shell size. Seems to be up to the job though....Thanks for posting it, Best Weasel.