Cone bore query

[SG500]

Attached are 3 photographs of a large cone bore projectile that has been fired.
My query is, keeping in mind this have clearly been fired and the rear flange is squeezed in, how is it that the front flange isn't.
Its not been messed with, there is no indication that anyone has tried to pull out the front flange.
The only explanation I can think of is that after exiting the barrel the centrifugal force was so great the front flange did not retain its squeezed shape and partly reverted to the original shape. Clearly a failed experiment as the projectile would then not be as aerodynamic.
Front flange diameter is between 67 and 69mmm
Rear flange diameter is roughly 58mm
Narrowest point of projectile (the part the front flange would squeeze into) is 40mm
All solid and INERT
Thoughts anyone?
Dave.

 

[Weasel]

Very interesting Dave, I wonder how much force would be required to cause the front flange to return to almost it's original shape. I look forward to finding out what it is.
Best Weasel.

 

[US-Subs]

Seems unlikely - steel just doesn't move that easily, and if it did then it would seem that it should have broken off, or even light impact after firing would distort it even more. Why are you certain that it has been fired? From your photos I do not see any obvious impact damage - ? Wouldn't a variation of the base component (unfired) be more likely?

 

[beihan62]

Wild guess,could this projo have originaly had an alloy sabot/projo body that would be reduced in diameter in the bore when fired and this has since corroded away,?
Don,

 

[SG500]

Seems unlikely - steel just doesn't move that easily, and if it did then it would seem that it should have broken off, or even light impact after firing would distort it even more. Why are you certain that it has been fired? From your photos I do not see any obvious impact damage - ? Wouldn't a variation of the base component (unfired) be more likely?

Good point Jeff thanks, I don't see any rifling marks on it.
Attached some photos of the others I have, some have obviously been fired. This is the only one where the forward flange is clearly larger than the rear of the projectile.
Also photo from Von Flanschengeschossen und Wolfranmkernen by Manfred Stegmuller, page 111, it shows what appears to be a fired and an unfired version of a similar projectile.

Dave.

 

[SG500]

Wild guess,could this projo have originaly had an alloy sabot/projo body that would be reduced in diameter in the bore when fired and this has since corroded away,?
Don,

Thanks, possibly, I've never seen such a thing on cone bore round though, perhaps someone has an example out there somewhere?

Dave.

 

[bacarnal]

Is it possible that in the (VERY) brief instant when the round leaves the muzzle the gasses swirled around the round and had enough force to "fill the sail" of the lighter front band? The first one you showed seemed that it was fully inflated. Don't know if it is possible but just a thought. Cheers, Bruce.

 

[pzgr40/42]

I think the aft bit simply isn't a flange at all.
look at how thick it is compared to the construction of the flange up front, that would not fold, the aft bit would jam iff it's caliber were bigger than bore.


my two cents,

Menno

 

[SG500]

I think the aft bit simply isn't a flange at all.
look at how thick it is compared to the construction of the flange up front, that would not fold, the aft bit would jam iff it's caliber were bigger than bore.


my two cents,

Menno

Thanks Menno.
A photo to show the rear of the projectiles.
They do appear to deform, the metal is relatively soft.
Dave.