Hispano cases

[SG500]

Just a few pictures of some unusual Hispano cases.
Four of them are 20x110 alloy cases with a variety of different coloured coatings one of the headstamps is also shown.
The one in the middle is a 20x117 brass case for one of the 20mm littlejohn rounds - no headstamp on this one.
If anyone has any information on the meaning of the different colours I would be interested in hearing.
Dave.

 

[TonyE]

20mm

The headstamp you show is a very nice early one. I suspect that most of the others are dated around 1948. My orange one was headstamped RG 48 P.

I do not know the scientific details of the different coloured anodised coatings that were tried, but a great deal of work went into this program before the project was closed. I have details of the summary of the program.

Aluminium cases were tried in all the British calibres of SAA at the time (1945-48) and I have seen aluminium cases in 9mm, .270, .280, .280/30, .303, 7.92mm, 20mm Hispano, 20mm Oerlikon and 30mm LV Aden. The Hispano is the one most commonly (or should I say rarely) encountered, but I suppose that is to be expected as the main priority was to reduce weight for aircraft and the 20mm HS was the service weapon.

Regards
TonyE

 

[TimG]

I have vague recollections of seeing both orange and green coloured cases in the same belt, which would seem to suggest there was little or no difference between them.

I do remember that these rounds were heavily covered in a wax preservative or maybe a lubricant (Anodising being a protective finish). Again, I have vague recollections, that this coating was the cause of problems in that there were breech fires and/or after a sustained firing the feed mechanism and surrounding area became sufficiently hot to melt the coating on the unfired rounds,which ran off into the working parts and solidified duly causing stoppages.

Regards

Tim.G.

 

[SG500]

Thanks Tony/Tim, some of these came originally from Herb Woodend, I understand from him that the purple one was extremely rare, perhaps we'll never know why that particular one was so special. I'll dig them out and take some pictures of the headstamps.
Dave.

 

[Falcon]

Really nice cases.

 

[SG500]

Thanks Falcon.
Attached a couple of pictures of the headstamps.
I've also attached a picures of some aluminium Aden cases - LV and HV versions.
All rounds inert/primers oiled etc.
Dave.

 

[SG500]

Here's a picture of the writing on the side of one of the cases - cold dye? Any ideas anyone?
Tim, interesting you mention the wax, one of them did have a white residue on it that was waxy.
Dave.

 

[TimG]

Dave,

In the anodizing process, once the metal has be subjected to the electrolytic action it is then placed in an organic dye which gives the workpiece its colour. There is a bit of scope as to what temperature that the dying is carried out. There being various pros and cons as to what temperature is used. However, over about 50 deg C the surface begins to seal preventing dying. In the final stage of the process the the article is placed in boiling water to totally seal the surface.
It would appear your particular case was one where the dying had been carried out at the lower end of the scale.

Regards

Tim.G.