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The Great War (1914-1918) Forum

13 pounder 9cwt


Rockdoc

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I've only come across this nature of gun as a sleeved-down 18-pounder used for AA work but I've now come to a reference that would make no sense in AA gunnery. I'm reading the Official History of the Ministry of Munitions, Volume X The Supply of Munitions and, in Pt III, Chapter III, page 62, VI Long Range Shells, it states Shells with six-calibre radius heads were being supplied in the following natures at the date of the Armistice:-

9.2-in gun, H.E and shrapnel

6-in gun, H.E. and shrapnel

6-in gun and howitzer, chemical

4-in A.A., incendiary

4-in A.A., shrapnel

3-in 20-cwt A.A., shrapnel and chemical

75-mm, chemical, incendiary and shrapnel

13-pdr 9-cwt, chemical

12-pdr 12-cwt, star shell

Anyone heard of the 13-pdr 9-cwt gun being used in the field? Presumably, its advantage over the standard 18-pdr was muzzle velocity?

Keith

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I know it is stating the obvious, but it sounds like gas or smoke. In either case I cannot imagine muzzle velocity being a factor?

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Range, I think. The section is headed Long Range Shells and the increase in radius of the shell nose it mentions made them more aerodynamic. The Army were desperate for greater range in every nature of shell because the Germans developed their technology earlier and were able to shell the British rear areas without the Allies being able to retaliate without moving up, making our guns much more vulnerable. The 13-pdr shell driven by the 18-pdr charge probably meant that this gun could send gas shells, which I think is what's meant by chemical, further into the German lines than the 18-pdr could. That's probably the only use we had then for a 13-pdr shell in the field because they weren't powerful enough in HE form to do much damage to German defences.

Keith

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Keith

I wonder if the 13-pdr 9 cwt, which was basically an AA gun, was used as a kind of high-angle howitzer to put gas or smoke shells behind cover onto German HQs or assembly areas? Possibly not, because the horizontal range might not be great enough, but maybe an option.

Ron

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I think using it as a howitzer is unlikely because the Army were demanding the heaviest possible shells for the larger howitzers by this time. A 13-pdr HE shell was incapable of damaging German defences so I can't see why they'd use chemical shells this way. If it gave them extra range, they could shell the reserve trenches and beyond with a gun that was still very mobile.

Keith

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Range, I think. The section is headed Long Range Shells and the increase in radius of the shell nose it mentions made them more aerodynamic. The Army were desperate for greater range in every nature of shell because the Germans developed their technology earlier and were able to shell the British rear areas without the Allies being able to retaliate without moving up, making our guns much more vulnerable. The 13-pdr shell driven by the 18-pdr charge probably meant that this gun could send gas shells, which I think is what's meant by chemical, further into the German lines than the 18-pdr could. That's probably the only use we had then for a 13-pdr shell in the field because they weren't powerful enough in HE form to do much damage to German defences.

Increased MV does not necessarily mean greater range. It's a matter of the ballistic coefficent often called 'carrying power', this means that if two projectiles are fired with the same MV, the heavier one goes further, obviously having the same ballistic characteristics is an assumption. The ballistics page on my web site explains this http://members.tripod.com/nigelef/fc_ballistics.htm .

As an example of the effects of ogive shape my ammo page states that the Mk 2 18-pr projectile was 2 crh (Mk 1 was 1.5) and in the 1930s a 4/7.5 crh shell was introduced which increased max range by 16%.

The highlighted text above is no doubt copied from somewhere but it's nonsense. All guns except that with the very longest range are outanged by another. It just means you may have to use a different type of gun to achieve the range you want. As far as CB is concerned its worth noting that official British practice was to use guns with their longer range for neutralisation (dispersion was greater but this didn't matter too much with chemical shells) and howitzers for destruction.

Of course in WW1 accurate long range fire was probably more miss than hit because the corrections for non-standard conditions while OK for shorter ranges were probably not good enough for reliably accurate long range map shooting. This means that accurate long range fire would have to have been ranged, since good positions for ground observation deep into hostile territory (eg HQ areas) were more than a tad sparse on the gound it meant air observation well over the other side's ground. I'm not sure that survival rates would be too high. Of course CB fire could be ranged by flash spotting and sound ranging, but it would be difficult with low productivity if there was a lot of firing going on.

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The highlighted text is my précis from the Official History that I'm reading so is quite likely to contain some errors. What I meant was that the British Army was always short of heavy-calibre guns in WW1, probably because no-one anticipated trench warfare but they didn't anticipate the size of the Army, either, and we all know how difficult it was to equip batteries with 18-pdr and 4.5in howitzers for quite a long time. The Germans appear to have developed their shell designs to allow greater range for a given gun type earlier than the British did. That means, obviously, that they had more guns able to hit more targets than the British did and those guns could be effective while being out of the range of their British equivalents. As I wrote in that précis, the British could not return fire effectively without moving up and, thereby, becoming even better targets. The OH records endless demands from the Army for any development in design that gave even a few yards of increased range - and they wanted them yesterday.

As I wrote in my fist post, I have no idea whether the 13-pdr 9-cwt gun was used in the field except as an AA gun because the OH isn't clear about that (this section is about supply of munitions.) I am surprised that it was being considered for use at this late stage of the War because of the lightness of the shell but it clearly was because they were making chemical shells for it. The advantage claimed for this gun over its 13-pdr 6-cwt predecessor in AA use was muzzle velocity and, logically, the 18-pdr charge should project a 13-pdr shell further than the 13-pdr charge, all things being equal. The heading of the table is Long Range Shells so it would make sense that a need was identified to throw a lightweight chemical shell a relatively long way. I cannot see what they would use a 13-pdr HE or shrapnel shell for in 1918 when the supply of 18-pdr and 4.5in ammunition was in reasonable balance so it looks as if the Army intended to use this type of gun for the specific purpose of firing chemical shells. To have a gun to fire only one type of shell seems illogical unless the Army had identified quite a large niche but I can only speculate about that.

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To have a gun to fire only one type of shell seems illogical unless the Army had identified quite a large niche but I can only speculate about that.

Keith

Looking at your original post, it seems that the Ministry of Munitions only produced one type of shell with a six-calibre radius head for the 13-pdr 9cwt.

This suggests three other possibilities:

1. The M of M produced other shells for this gun, but not six-calibre radius head;

2. Another supplier, perhaps in Canada or the USA, was producing other shells for this gun;

3. The gun used other shells, possibly even of six-calibre radius head, which were also used by (and even made by the M of M for) other natures of gun.

What do you (and nigelfe) think?

Ron

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This suggests three other possibilities:

1. The M of M produced other shells for this gun, but not six-calibre radius head;

2. Another supplier, perhaps in Canada or the USA, was producing other shells for this gun;

3. The gun used other shells, possibly even of six-calibre radius head, which were also used by (and even made by the M of M for) other natures of gun.

I think the critical point is the heading Long Range Shells, which suggests these are for some special purpose bu what that might be is anyone's gues at the moment. As for your points:

(1), Other shells (mostly HE) were produced for this gun for AA use. The gun was a stop-gap development after the low MV of the 13-pdr 6-cwt quickly made it ineffective as aeroplanes were developed with increased speed and height capabilities. It was a sleeved-down 18-pdr but retained the 18-pdr breech, allowing a greater weight of charge compared to its predecesor for the same weight of shell. It's been a long time since I had anything to do with aerodynamics but, IIRC, reducing the drag reduces the dynamic pressure acting on the surface of the projectile. Low dynamic pressure is said, in the OH, to have created problems with the burning of the fuzes so my guess would be that AA shells had a smaller-radius head.

(2) I suspect that these shells were produced in very small numbers relative to the production of the "standard" natures so would have been produced by Woolwich rather than one of the other munitions factories. The OH discusses the disruption caused by the need to make small numbers of certain types of shell.

(3) The gun used a shell that could be used by it or the 13-pdr 6-cwt but the rounds were not interchangeable between them The 9-cwt effectively had an 18-pdr cartridge case that was necked down to the diameter of the 13-pdr shell.

Keith

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Ron

Canada supplied 13 Pdr Shrapnel shell empty this was an odd lot of 79,550 which was ordered in 1916 and shipped in December 1916, Cartridge cases of the same size (for 13 pdr) amounting to 1,004,011 were manufactured and shipped. Apart from these lots, the principle shells were undertaken and produced as follows:-

15 Pdr Shrapnel Shells. The total number of manufacturers employed in making 15 Pdr Shrapnel Shells were comnparatively few. After the first order for 100,000, the demands were chiefly for the 18 Pdr shrapnel; only 302,208 15 Pdr were shipped to England. Five machining and assembly makers and 28 maker of components dealt with the entire output. The largest number of any one component made by one company was 300,000 shell forgings. These were made by Nova Scotia Steel Company of New Glasgow. The largest number of shells made by any of the maching companies was 180,00 by the Electric Steel Metals Company of Welland.

18 Pdr. Shrapnel Shells. With regards to the 18 Pdr. shrapnel the nuber of manufactures who machined and assenbled shelss grew from 10 to 61, and a total of 381 makers of components in Canada and 24 in the United States, making in all 466 manufactures engaged in making this nature of shell. Of the many Canadian manufactures who distinguished themselves in the excellent production they made, one which had the largest daily production rates was the Canadian Fairbanks Morse Company, of Toronto, amounting to 8,231.

The Rome Manufacturing Company of Rome, U.S.A. produced as many as 40,000 copper driving bands per day, and the Canadian Cartridge Company of Hamilton, Ontarion reached the enormous daily output of 40,000 18 Pdr cartridge cases, and made a total of 14,510,600. The Montreal Ammunition Company followed closely upon this daily output.

18 Pdr High Explosive Shells. There were 66 manufactures who assembled and machined and 20 who made components. The Transcoma Shell Company, afterwards called the Universal Tool Company of Toronto, had the largest daily output amounting to 3,672, and also made the largest number 476,506 shells.

4.5in Howitzer High Explosive Shells. There were 359 manufacturers employed in the manufacture of this shell, 105 machining and assembling, and 254 making components. Thirteen U.S.A. manufactures supplied components. The Dominion Copper Products machined and assembled the largest daily output of 2,098 and made 783,272, the largest number made by any one company. The company also made the largest number of 4.5 in cartridge cases, namely 8,246,000. Manufacture of shells commenced in February 1915, and the total number made was 12,607,091. There were also 11,995,215 cartridge casaes made and shipped.

60 Pdr High Explosive Shells. Manufacture of 60 lb. shells did not commence until May 1915. There were 26 manufacturers machining and assembling, 49 making components in Canada and 5 in the U.S.A. The total weight of materials used per shell was 56.34 lb, and 1,104,312 were delivered.

6 in High Explosive Shells. Manufacture of 6 in. shells did not commence until November 1915. There were 53 manufacturers machining and assembling, 172 making components in Canada and 16 in the U.S.A. The total weight of materials used per shell was 87.68 lb, and 11,078,534 were delivered.

8 in High Explosive Shells. Manufacture of 8 in. shells did not commence until November 1915. There were 12 manufacturers machining and assembling, 31 making components in Canada and 16 in the U.S.A. The Canadian Fairbanks Morse Company of Toronto made the largest daily output of these. It employed a very large number of women. Their factory was a model of engineering skill and organisation, 1458 of these shells were produced daily each weighing over 200 lbs. were produced daily, by February 1918 a total of 753,831 were completed.

9.2 ih High explosive Shells. This was the largest shell manufactured in Canada. There were 11 companies machining and assembling, 28 making components in Canada, and 22 in the U.S.A. Manufacture commenced in nNovember 1915 and first deliveries in May 1916. The total weight of the metal per shell was 299.67 lbs. Total shipped by Dec 1918 782, 355.

John

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Using a long range 13-pr for field arty doesn't make a lot of sense, lethality is low (its the smallest calibre used) and at long ranges dispersion is likely to be considerable.

UK had no real shortage of heavy arty, that's why they could transfers stocks to the US and Russia (although these were curtailed by the revolution). What was missing was manpower for additional batteries. It was a people not a materiel problem.

Increasing range increases the area of influence (to use a modern term), this is always desirable. It also means that a battery can cover a wider area in front of friendly troops as well as a deeper area without moving position. In some ways the wider area is more important than the deeper because it means more fire can be concentrated.

The CB stuff is a fair amount of nonsense, it harks back to the 19th century notion of the artillery duel which effectively died in gunner minds during the Boer War. The only time the CB battle turned difficult for the BEF was Passchendaele, and the root of the problem was that the terrain gave German good observation over the gun areas. Even there the main (but not sole) German effort seems to have been neutralization with gas rather than accurate HE fire for destruction. The BEF developed a far more effective CB system than the Germans did, guns are only one element of the system. Cambrai was a significant CB victory for the BEF, they were no way disadvantaged by German range advantage. Having guns forward is not necessarily a disadvantge, you need them there to support a succesful attack once it starts getting in, of course the problem then became arty communications.

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