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30mm KCA

SG500

SG500

Well-Known Member
Premium Member
4 Feb 2011 077.jpg4 Feb 2011 079.jpg4 Feb 2011 083.jpg4 Feb 2011 080.jpg4 Feb 2011 076.jpg4 Feb 2011 081.jpg4 Feb 2011 082.jpg4 Feb 2011 078.jpgI was walking around Stoneleigh last weekend hoovering up every available Rarden case I could find to go with a heap of projectiles I'd just got:wink: and ended up with a couple of brass 30mm KCA cases by accident (when I got them I thought they felt a little heavy for Rardens). I then compared them to the Rarden rounds which are the KCB profile - see photos, the Rarden is the one in the middle, the KCA rounds are either side.
I have a few queries about the KCA ones:-
There are no headstamps but the primers are stamped CY (Chorley presumably) with an 89 date on them. Considering (according to Wikipedia) the Saab AJ/JA 37 Viggen (which is as far as I am aware the only aircraft to use the KCA round) was phased out in 1990 these cases seem very late........any thoughts?
The cases have circular marks on the bottom, I'm presuming they are made when the round was rammed home? There is one hole in the side of one case and it has 3 imprints on the base. The other case has a repaired hole and a hole and 3 imprints on the base with another 3 superimposed over them. I'm assuming they are pressure test rounds one of which has been used twice..............any thoughts?
I always like getting odd stuff like this especially as they're cheap. The research part is just as much fun as getting them in the first place.
Dave.
 
Hand made cases ?

30mm KCA Primer.jpgTony you are correct that KCA rounds are generally made from Steel !

One other thing SG500 is that your cases have a small Chorley produced Primer in them but the KCA rounds I have seen have all had a very large "Electric" initiated Primer ??

The rings on the bases will almost certainly have been caused by excess pressure when the cartridge was fired or when the case set back onto the Breech face with the pressure.

I think that if you look very carefully you will find that these cases are "Hand turned" on pretty much a "one off" basis.
Very nice find indeed!
 
Tony Williams said:
That's interesting - I thought that the KCA ammo was steel-cased (certainly my dummy round is).
Click to expand...

Tony correct me if I'm wrong, I'm using the term KCA rather loosely. Its a brass case with a KCA profile and a KCA length, it could be something else possibly?
 
Perhaps we are all missing the obvious here !

GAU 8 as fitted to the A10 Tank buster !

These cases will be the same size as the 30mm cases for that gun.???????????????????????

Whilst the Americans had the weapon we must surely have done serious experiments with the Ammo including "home grown" which is a possible answer to Dave's enquiry.
 
The GU8 has got a taller neck than the Rarden and looks right for one of these in Daves photo.
Think you have hit the nail on the head Chris,perhaps case lenght would confirm?

Tony
 
As far as i know,the GAU8 only uses alloy (aluminium) cases.

cheers
Bob
 
I thought the GAU 8 only came in alloy too, but Chris could be right, most people think Adens only come in brass but I have several alloy ones in different lengths..........anyone else have any thoughts on that?
Dave.
 
The GAU-8/A 30x173 ammo differs in three ways from the KCA 30x173 ammo on which it is based:

1. Light alloy rather than steel cases

2. Percussion rather than electric priming

3. Plastic rather than steel driving bands.

The 30x173 ammo for the KCA is now obsolete as the SAAB Viggen which carried the gun has been retired.

The percussion-primed 30x173 is not just used in the GAU-8/A but also in the Bushmaster II / MK44 Chain Gun (used in an increasing number of light armoured vehicles, and also by the RN in their new remotely-controlled ship mounting), and in the Mauser MK30 cannon (used in various AA and AFV mountings). However, the case material used with the MK44 and Mauser is now generally steel rather than light alloy, weight saving not being such as issue as it is in aircraft.

I do not know of any service use of brass-cased 30x173 ammo. I expect that some might have been used during the development of the KCA in the 1950s and 60s, but that's all.

The 30x170 Oerlikon ammo used in AA guns (including the older RN mountings), which was used as the basis for the Rarden round, has been brass-cased in the past but is now steel - apart from the Rarden ammo itself, of course, which has always been brass. This is clearly a different shape from the 30x173 and is not interchangeable (although I could tell you a funny story about that...).

30x113B ammo (which may only be 111mm long) comes in three versions (which are generally not interchangeable, although I believe the M230 Chain Gun can fire all of them):

1. For the Aden gun (almost invariably brass cased, some foreign production may be steel cased).

2. For the French DEFA/GIAT/Nexter cannon (always steel cased AFAIK).

3. For the M230 Chain Gun used on the Apache helo (always light-alloy cased).

Hope this clears up any confusion!
 
Thanks Tony. Yes happy with all that, the odd thing about these brass cases is they have 89 primers in them which I think are genuine (one unscrews but doesn't come out because the top of it is belled possibly from when it was fired) the other is screwed in and won't budge. So yes, they are a mystery still.
Aden cases definitely came in alloy form in expt version (ref Labbet's excellent book about it mentions how many were produced, also I had 3 such cases in LV and HV form from Herb W).
Dave.
 
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