13 pdr anti-aircraft gun

[RodB]

I've been digging up conflicting info about what was used to produce 13 pdr anti-aircraft guns - some sources say 13 pounder guns which were no longer useful on the Western Front, others say relined 18 pdr barrels using 18 pdr charges but 3 inch shells.

So what actually were they made of ? Were there in fact 2 different guns ?

The one here looks like an 18 pdr to me - is it the "13 pdr 9 cwt anti-aircraft gun" using a 18 pdr charge and 3 inch shell ?

thanks

Rod

[ian turner]

I seem to remember a discussion on this topic a year or two ago. Try a search of the forum - it might give you the answer!

Ian

[Hoplophile]

According to the Book of Armaments (also known as British Artillery Weapons and Ammunition 1914-1918, by Hogg and Thurston), the Royal Artillery fielded one type of 18-pounder anti-aircraft gun, two types of 3-inch anti-aircraft gun and three types of thirteen-pounder anti-aircraft gun.

One type of 13-pounder anti-aircraft gun was the '13-pounder, 9 cwt'. This was an 18-pounder that had been relined with a 3-inch (76.2mm) barrel sleeve. This sleve, which had the same bore as the barrel of a standard 13-pounder, allowed the weapon to fire 13-pounder shells. At the same time, the larger chamber of the gun made it possible to use the (much larger) propellant charge of an 18-pounder. In other words, the 13-pounder, 9 cwt fired a 13-pound shell that flew much faster than the 13-pound shells fired by other 13-pounders.

In World War II, this combination of a relatively small projectile with a relatively large propellant charge was used to maximize the muzzle velocity of anti-aircraft and anti-tank guns. In the world of small arms, the same principle is used to create 'varmint rounds', which are used to hunt animals in situations where the condition of the meat is not a concern. (In the patois of the American West, a 'varmint' is a fur-bearing pest of one sort or the other.)

[RodB]

Thanks for the help... I've found that book being offered for about US$200 - amazing for 225 pages. Especially when I convert it to Aus dollars. Is it printed on gold leaf or what ? But I get the impression it's the must-have reference for British WWI artillery. Suggestions as to how I can locate a cheaper copy ? I assume that in US, Britain and Europe you can trawl around secondhand bookshops but the range availalable here is much narrower and widely spread.

While we're on the topic - is there a defining characteristic to visually identify between the 13pdr and 18pdr ? The 18 pdr seems to sit much higher on the carriage than the 13 pdr, correct ? But the barrels of both look very similar - the 13pdr recuperator housing looks smoothly cylindrical whereas 18 pdrs appear to be corrugated with some sort of canvas protector wrapped round them, is this correct ?

The photo below is identified in "The Great War" series of propaganda books as "Royal Horse Artillery" so I presume it is a 13 pdr ? Or is it in fact an 18pdr ?

whereas the image below purports to be an 18 pdr, but it looks very similar ??

[chris mccarthy]

They are both 18pdrs, some time in 1915? RHA were re gunned and issued with 18 pdrs.

A very good book on basic artillery :

Allied Artillery of World War One. Ian Hogg. Crowood Press. ISBN 86126 104 7

[Hoplophile]

The bad news is that British Artillery Weapons and Ammunition will cost you a pretty penny on the used-book market. The good news is that the same information can be found in lots of other books, most of which were, mirabile dictu, also written by Ian Hogg. Like most authors of books of this sort, the late Master Gunner Hogg was a practitioner of 'literary ecology', so information found in one book often ends up (albeit in a slightly different form) in another.

[RodB]

The bad news is that I have no budget for buying any books at present.

I have here yet another photo below, from IWM, Aus and British troops at Morbecque 31 August 1917.

The barrel appears longer and thinner than the photo above, at least in comparison to the recuperator. Or is that because the picture at top shows the barrel in the recoil position ? The cartridge below appears to match the shell i.e. doesn't appear fatter, which is what I'd expect to see if it was the 13 pdr shell with 18 pdr case. Or wasn't it visibly different ? Any photos of the hybrid round anywhere ? So is this a genuine 13 pdr AA gun rather than the 13/18 pdr variety ?

The wartime photographers appear to have loved these scenes of gunners clustering round the AA gun staring at the sky... most of them I assume were posed for propaganda value ?

Rod

[Hoplophile]

The picture is a hard one to puzzle out, for the men are standing in front of those parts of the gun that would allow one to distinguish a 'pure' 13-pounder from a 'hybrid' 13-pounder 9 cwt. Similarly, the man holding the shell has his hands over the neck of the round, thereby making it hard to determine if it is an ordinary 13-pounder round or a hybrid round with a necked-down 18-pounder cartridge. (As the difference in diameter between the 13-pounder shell and the 18-pounder cartridge was only about 12 mm, the necking-down does not seem to have been particularly pronounced.)

[RodB]

The round appears to have a neck, and the cartridge appears pretty hefty :-

???

Rod

[RodB]

Apologies for resurrecting this topic but I still have questions. I'm satisfied that the blowup above of the shell for the gun surrounded by Australians shows 18 pdr cartridge necked down to 13 pdr shell.

And the gun in the photo matches the one below from the Duxford IWM museum, which I understand is a 13 pdr 9 cwt gun on a Type J Thornycroft lorry :

However, the barrel of the gun that I started the thread with protrudes much less beyond the recuperator, which apparently was a feature of the 13 pdr barrel - it was shorter. So is my photo (below) of a real 13 pdr in fact, or is the apparently shorter barrel an illusion or caused by it being in recoil position ? :

Finally, I have the diagram below by Ken Musgrave, labelled as a 13 pdr 9 cwt aa gun. I have seen quite a few pictures of this type, which to me looks like 2 recoil buffers/recuperators above a barrel (??). But to me it looks totally different to the gun on the Thornycroft. They can't both be the 13 pdr 9cwt surely ?

So - which is the real 13 pdr 9 cwt ?

cheers

Rod

[johnreed]

Photo1

Photo 2

The 13 Pdr as in the drawing was originally a 3" gun developed for commercial sale by Elswick Ordnance Company, it differed from the 13 Pdr by having a shorter barrell and by having a lower muzzle velocity. It also had a Nordenfeldt screw breech mechanism. It also had the additional recuperator spring housing mounted over the usual recoil system, so the gun would return to its normail position in run out in the high angle. There were six of these guns offered by Elswick Company to the Army and were promptly bought eventually all six guns ended up in france. See photo 2. I will ignore the Marks of mountings and types of lorries they were mounted in.

The next was the 13 Pdr 6cwt Mk 1 & 2 which was a conventional 13 Pdr with o mounting on simple pedestal supporting the yoke which carried the gun and cradle. See Photo 2 The Mk 2 Carriage was an improvement which had deflecting gear fitted which allowed the gun to be travesed 10 deg. either side of centre.

The MK 3 had a Carriage retaing catch fitted

The Mk 4 13 Pdr QF had an additional buffer spring casing mounted on the origional recoil system but usuing the normal 13 Pdr fixed ammunition.

The 13 Pdr 9 cwt had the lined 18 Pdr firing the 13 Pdr Shell but usuing the taper necked 18 Pdr cartridge case. In some cases there was an oil reservoir mounted on the spring cases to help prolong the spring life.

John

[RodB]

Thanks for that John. I'll recapitulate the situation as I now understand it, please correct if wrong :-

Elswick Ordnance Company's 3 inch gun, identified by short barrel and 2 recuperators :

Your picture, with Ken Musgrave's diagram below it - wrongly labelled ?

Followed by the 13 pdr 6 cwt (your photo 1 which I assume you refer to as photo 2 in your narrative). Also identified by the shorter 13 pdr barrel in relation to the recuperator :-

My photo below yours the gun on Thornycroft truck also appears to be the same gun, a 13 pdr 6 cwt :

We then get to the 13 pdr 9 cwt where they finally got it right. Identified by the longer barrel of the 18 pdr, and the oil reservoir at the end of the recuperator if present :-

Aussies round gun, and blowup of shell, appearing to show neck on cartridge

with example at IWM Duxford below it :

???

Thanks

Rod

[RodB]

I've also seen the following gun on various trucks. Has long barrel and apparently an oil reservoir on the recuperator :

Is it the 18 pdr aa gun or a variation on the 13 pdr 9 cwt mount ?

And then I have Ken Musgrave's drawing of a "3 inch 20 cwt". Some flavour of 13 pdr ?

???

Rod

[RodB]

Can somebody confirm that AA guns can be identified by barrel length : those originating as 13 pdrs (including the 13 pdr 6 cwt) by short barrel, those originating as 18 pdrs (including the 13 pdr 9 cwt) by the long barrel ? I understand the defining visual feature of the 18 pdr (and hence presumably the 13 pdr 9 cwt) was its long barrel, esp. relative to the recuperator; and the 13 pdr's major visual feature was its short barrel, only a little longer than the recuperator.

So I would expect barrel length to visually separate the 13 pdr 9 cwt and 6 cwt. Leaving aside the apparently unrelated "3 inch" family for the time being (some with short barrel, as John mentions above, but the only important one in WWI was apparently the 3 inch 20 cwt which looked nothing like the others and is instantly identifiable by its massive barrel).

This tallies with the guns explicitly labelled as 13 pdr 9 cwt in General Farndale's History of the Royal Regiment of Artillery books. So based on barrel length, the following should be 13 pdr 9 cwt, except that the guns below lack the (18 inch ?) thin tube-like thing above the rear of the recoil mechanism (I don't know what you call it) that appears in pictures Farndale labels as 13 pdr 9 cwt. This tube does appear in other photos below. Relevant ? :

and also the following with a long barrel. But it has the same sort of multiple metal plate shield-like arrangement in front of the mounting (I don't know what it's for or what you call it) as a gun in Brigadier Routledge's book on AA artillery in the same series, but that gun has a short barrel and he labels it a 13 pdr 6 cwt - see my next post for scan. So was the mounting arrangement of the gun below used for various guns ? :-

and (which Brigadier Routledge merely labels a "13 pdr") but has a long barrel, and hence also 13 pdr 9 cwt ? :-

... continues in next post, limit of 3 imagfes per post ...

[RodB]

Finally, if a short barrel rules out the 13 pdr 9 cwt, then we are left with either the early 3 inch John mentions, or the 13 pdr 6 cwt as John's post appears to imply the below are, correct ? These pictures do show the 18 inch ? tube-like thing above the rear of the recoil mechanism. What is it, does it tell us anything about the gun ?

Brigadier Routledge labels the following as a 13 pdr 6 cwt in his History of The Royal Regiment of Artillery, Anti-Aircraft Artillery :-

To my untutored eye the barrels appear to be only a little longer than the recuperator, which fits with the 13 pdr, and the cartridge case appears slim with no neck, but the barrels look longer than the barrels in the 2 pictures above it. Optical illusion ? But the shield-like affairs are the same as in my picture in the previous post of a similar gun but with a longer barrel. So do we have 2 main families of mounting, both used for both families of gun ?

Further thought : John mentioned : "The Mk 4 13 Pdr QF had an additional buffer spring casing mounted on the origional recoil system". Does this mean that the additional buffer spring casing was mounted lengthwise, making the total recuperator longer ? Or else how did it differ visually from the original 13 pdr ? Brigadier Routledge is pretty sketchy on the guns themselves. He merely says that the first attempt at using a 13 pdr had a second recuperator added to assist runout, but this was dispensed with "when the mounting was improved... in this form it became the 13 pdr 6 cwt, or 13 pdr QF Mk 3, issued in 1915". He also mentions 6 3 inch QF guns coming from the Navy early on. Is this garbled ?

I have this picture from the IWM claiming to be in Salonika in 1916 - it plainly has 2 recuperators, but Brigadier Routledge only mentions 13 pdr 9 cwt and 13 pdr 6 cwt going to Greece. ??

He also displays a 12 pdr 12 cwt in a relative performance table, firing a 12.5 lb shell at 2200 ft/sec with 36 in UK and 10 in France at the Armistice. ??

???

thanks

Rod

[ian turner]

I cannot add any clarification to these questions, but just ask whether the small 'tube' on top of the recoil mechanism is a sighting tube, for aiming purposes?

Ian

[morrisc8]

13Pdr 9 Cwt Shell case in my collection.

[stevenbecker]

Mate,

From my reading many Ex cavalry (Horse Batteries) 13 Pdrs were replaced by 18 Pdrs during the war, and the surplus used in other ways like AA guns.

S.B

[morrisc8]

5 hours ago, stevenbecker said:

Mate,

From my reading many Ex cavalry (Horse Batteries) 13 Pdrs were replaced by 18 Pdrs during the war, and the surplus used in other ways like AA guns.

S.B

Hi Stevenbecker,

                            I think my 1916 dated 13Pdr was used for AA use and reused in 1917 but can`t ID all the markings on it.