105mm Abbot Proof?

[Falcon]

This morning at the car boot sale I picked up what I thought was a standard 105x326R case. it wasnt until I got home that I realised it had the remains of a purple stripe across the case head, which usually indicates a proof round in British service. It is a 1962 Dated example (see photo below):The two purple lines indicate remains of the purple stripe.

What do the "Three rings" marking next to "RLB" for Royal Laboratories and "RW297" mean? This case still has the black plastic collar in place at the neck. Was the projectile gripped by this? Does anyone have any photos or diagrams of this round?

There was no primer with this case, the primer hole was blocked up by an old brass drawer handle screwed into a small piece of wood inside the case, which I easily removed by splitting the old, dry wood with a chisel. This case had bits of soil inside, so I believe it was used as a plant pot.

EDIT: I forgot to include that traces of the ink stampings "L36A1" "SUPER" can still be clearly seen if the case head is viewed at the right angle. According to an online source, the "L36" is a smoke round, so is the plastic collar possibly exclusive to smoke rounds?

 

[TimG]

RLB is actually the monogram for Birtley, an ROF in Newcastle upon Tyne
Violet signifies experimental ammunition
In engineering, a continuous line of circles on a nut or bolt signifies "Unified thread" (an American thread). I suspect that these circles signifies that this case uses a primer with a Unified thread. In the early sixties the majority of UK ammunition would have used Whitworth thread.

Tim. G.

 

[Falcon]

Thanks, that explains alot. Thinking about it, I have seen that symbol on the Bridgeport milling machines I use at college.

I never knew that RLB Was ROF Birtley, I always assumed it was Royal Laboratories Woolwich (although 1960s would have been too late).

Do you know what the plastic collar is for? Should it be on all cases of this type? If so, the other case of this type I have doesn't have one, meaning someone took it off. The other case is headstamped "ECC" as the maker's mark. Do you know who this refers to? I thought Elswick, or is it too late?

 

[waffenamt]

Hi Falcon,I see that your case has similar markings to that one ive posted in your other thread.


cheers


waff

 

[bombmonki]

Falcon,
I am pretty sure the RW297 refers to the drawing number/design for the cartridge. This is pretty common on UK proof ammunition.

Leo

 

[TimG]

Ive just consulted my 1961 book on primers. It would appear that with the introduction of L series primers the switch from Whitworth to Unified thread was made. The description for each states; Three indented contiguous circles indicate that the primer hole threads are of the Unified type

As for ECC I have no listing, someone suggested that it is the monogram for Edward Curran of Cardiff. This would seem to be highly likely as in the Great War (Edward Curran Enginering, Cardiff) they were manufacturing drawn warlike stores i.e. cartridge cases. In 1938 (Edward Curran Co. Cardiff) they submitted a patent in relation to the annealing of cartridge cases.

Regards

Tim. G.

 

[Falcon]

Thanks, do modern "L" type primers still use unified threads or are metric threads used today?

I googled Edward Curran of Cardiff, and the company was obviously still around in 1962, as this is what I found:

1973 Edward Curran Engineering Limited of Cardiff, the UK leading makers of steel baths, joined Reed Building Products division, adding steel and acrylic baths to Twyfords range of sanitaryware.

 

[TimG]

I would very surprised if we didn't use both and there may well be something left that still uses Whitworth primers. A lot of British ordnance is not just foreign designed it is also foreign manufactured*. So, our main suppliers are going to be the States who are still clinging on to Imperial and Europe who've been Metric for over a century.

* We are now down to just three ROFs, of which only one; Birtley has the capability to produce large calibre cases. But, the equipment is 'mothballed' and hasn't been used for several years. There is the possibility that Birtley may be closed. This would cause untold problems, not least to the Royal Navy as their 4.5" armament uses a case unique to us.

Regards

Tim. G.

 

[Falcon]

That seems like madness...close the only factory in the country that can produce large calibre cases. If another major conflict ever breaks out we are finished as we now have so little capacity to manufacture ordnance (or anything else).

Are we currently using existing stocks of 4.5" ammunition or rounds made on reloaded cases?

 

[Falcon]

Can anyone post any photos/drawings/diagrams of this calibre? Is the black plastic collar on all loadings?

 

[Chris 42 RQ]

Black Plastic Collar !

Regarding the "Plastic" ring on the Abbot case-I cannot view the picture of yours, but if it is the same as the one in the attached picture then the answer as to its use is-

When using the Gun with a "Super charge" the case needs to accomodate a small amount of extra propellant and with the increase in volume of that propellant it was found necessary to add the black plastic ring-also with this charge it was absolutely vital that the projectile was well seated on the engagement section of the rifling so as to prevent serious "Gas erosion" of the bore on firing.

As for the remnants of a "Purple" stripe, this would indicate that it was an "Experimental" round for some reason that may well not be evident after use;- Ie a special loading or just a design change-there are a lot of things that will need to be tested before approval is gained on any modification and all of these will mean the round will have a "Purple" stripe somewhere easily visible on either the case or projectile or sometimes both.

 

[Falcon]

The ring in the picture on yours is definitely the one I have on my case, although mine has been polished so the ink stampings on the case wall are gone, however the remains of the ink stampings on the head suggest it was a smoke round with the "Super" charge. Thanks for your help in clearing this up.

I have another case without the plastic ring, but it looks like someone took it out as it has left a mark round the inner case wall at the neck.

I have never seen a complete inert round for sale in this calibre, are they hard to find?

 

[Chris 42 RQ]

Missing collar

In answer to your question, not all cases have the black extension Collar as on most rounds it is not required.
But all (those that I have seen) cases have the four indents around the neck to fit a "Polystyrene" bung into once the Gunner has either added or taken the required bag charges for the shot being taken.

see the attached picture-it is of the American 105 MM How case with all of its Separate "Bag Charges" any of which can be ommited for closer shots, sadly this one is "Instructional" and does not have the same indents to secure the Bags.

 

[spotter]

these the bits you mean chris
pic 1 super charge
pic 2 normal charge components
pic 3 normal charge

 

[Chris 42 RQ]

Right on the button

Spot on Spotter with your pictures-indeed they are the bits.

I note that your picture also has the moulded cardboard "long" extension, those you very rarely see.
Thanks
Chris

 

[Falcon]

Thanks, now I've seen the pictures its clear how this round works. All the time I took the "FD" on the headstamp to mean "Fixed", but that is obviously not the case as it is a separately loaded round from the pictures. Thinking about it, I have seen examples of the longer necked 105mm case for the L7 tank gun, and that is marked "105MM TK", so does "FD" mean "Field"?

So my round with the collar obviously contained the super charge, but was marked "L36A1" as well, which apparently is a smoke shell. Was there a specific charge only for use with the L36A1 smoke shell?

What is the purpose of that long cardboard extension on the normal round? The projectile must have had to be a long way into the barrel in front of the case.

Thanks for all the info so far.

 

[spotter]

Yes FD is field
Found this info about the extension on the one i showed
The Holder Charge is a moulded polystyrene or fibre cap . At the open end the
holder has an interrupted right hand thread formed on the external surface to permit
the holder to be screwed into the Cartridge Case.
The Holder Charge is used to contain the Charge Increment No. 5. Should the
Charge Increment No. 5 not be required it may be unscrewed from the Cartridge
Case.
ref the black collar the only reference i can find to this, is that its used with super charge​