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110 mm british tank gun


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#1 saul

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Posted 10 June 2011 - 1250 PM

i need information abouut this gun.
all i know is that it took part in a competion between british,american
and german suppliers which was held in 1974-1975.
the british gun lost.
the first prototype was designated as exp-7 and the second exp-14.
any help and references will be much appriciated.
thank you in advance.
saul
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#2 commander

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Posted 10 June 2011 - 1527 PM

Exp 7 was built and tested, it was designed to replace the L7 105mm IF IT WAS REALLY NECCASSARY which it was not, big problem with it was the extraction of the case whic hwas wholly brass. The Exp 14 used a semi combustubile case with stub base, while it is true it was entered in a competion to secure a weapon for FMBT it did not loose as uK dropped the project in favour of 120mm as they saw this the way to go.
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#3 Przezdzieblo

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Posted 10 June 2011 - 1631 PM

Welcome saul,
UK 110 mm guns was planned for "easy" replacement for widespread 105 mm L7 and it`s clones. It was designed to fit into 105 mm tank turrets without need for much metalworks. And it was said to be equivalent of Chieftain`s 120 mm in terms of firepower.
First round of trilateral (UK-US-FRG) gun testing gave Brits the idea, that 110 mm gun and APDS ammo are not as good as it was thought. This is why they changed to 120 mm (development which lead to L30) and started works with APFSDS ammo.
Basic informations could be found in Chapter 5 of "Cold War, Hot Science" (by R. M. Ogorkiewicz). More - The National Archives and Bovington Museum library only, I guess. But if you have some specific questions, ask :)

Edited by Przezdzieblo, 10 June 2011 - 1646 PM.

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#4 Old ROF

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Posted 10 June 2011 - 1931 PM

i need information abouut this gun.
all i know is that it took part in a competion between british,american
and german suppliers which was held in 1974-1975.
the british gun lost.
the first prototype was designated as exp-7 and the second exp-14.
any help and references will be much appriciated.
thank you in advance.
saul


Although the EXP-7 was the first 110mm calibre ordnance created by RARDE, this was basically just a bored out 105mm L7 barrel - with the forward end of the chamber suitably amended to match the new bore diameter, the operating pressure was no greater than the standard L7. This was followed by the 110mm EXP-8 (known as the 'Sales Gun') which was based on the same exterior profile as the 105mm L7 barrel but was capable of sustaining higher operating pressures.

These were both superceeded by the 110mm EXP-14 which had a higher operating pressure and was designed with separately loaded stub case ammunition. The use of the stub case minimising the potential problem of case sticking on extraction/ ejection. This ordnance had a vertically opening breech instead of the sideways opening of the 105mm L7 system. This system was the one used in the original tri-partite evaluations.

Out of interest the 120mm M7 quoted earlier in the "Cold War, Hot Science" book as the replacement for the 110mm following the tri-national firing trials should really be the 120mm EXP-19M7. This ordnance was re-designed as the EXP-19M13A specifically to suit fitment to the XM1 vehicle in terms of mounting centre of gravity, and used stub case ammunition.

The Challenger 120mm L30 ordnance was derived from the experimental 120mm EXP-32 ordnance - which was itself developed from work done on the 120mm EXP-28 which was intended for the MBT80. Both of these guns used separately loaded, fully combustible case, ammunition the same as the 120mm L11 ordnance.
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Edited by Old ROF, 11 June 2011 - 0145 AM.

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#5 JWB

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Posted 10 June 2011 - 2125 PM

Cold War, Hot Science >

http://books.google....e&q=EXP&f=false

If that link fails slightly just go to page 124.

Edited by JWB, 10 June 2011 - 2126 PM.

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#6 commander

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Posted 11 June 2011 - 1428 PM

OLD ROF glad you tipped up on this as I hoped you would, UK110 is always hard to pin down and i did not know about E8, the 120 from which L30 is developed is that the one in the TM?. Nice to see you again on here.
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#7 Old ROF

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Posted 11 June 2011 - 1748 PM

Stuart:
According to the information I have at this time there was a smoothbore barrel produced but it was a bored out version of the 110mm EXP14 and was matched to the EXP-14 breech. The modified ordnance was then used for ammunition trials. There were smoothbore barrel versions produced as well for the L11 barrel and the later EXP-32 barrel for experimental ammunition work.


Commander:
By TM do you mean the Tank Museum? It's been years since I've managed to get there but if you have any photos of the ordnance, especially the breech area, I could try and work out it's heritage fromits designations.

From what I understand the original 120mm EXP-19 variants started out as modified versions of the EXP-14 ordnance. The later EXP-19 versions being further developed with a new breech design enabling larger diameter stub case and chamber sizes to be used.

The next iteration of 120mm ordnance was developed for the MBT-80 program, this was the EXP-28 and had different mounting requirements compared with the existing Chieftain L11 system but could be shoehorned into modified Chieftain cradles. This went back to being a self obturating ordnance rather than using stub-case ammunition.

When the MBT-80 was cancelled the knowledge and experiance gained was incorporated into a new ordnance designated the EXP-32 - the 'New Technology 120mm'. This is what eventually became the L30 gun used in Challenger 2.

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#8 JWB

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Posted 12 June 2011 - 0155 AM

An aside is this thread on the abortive MBT80 >

http://208.84.116.22...showtopic=29702
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#9 saul

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Posted 12 June 2011 - 0339 AM

Guys, thanks a lot. You helped me a great deal.

1. Please note that Orr Kelly's book, ch. 4, is a good source for general information about the tripatriate competition held during 1974-1977.

2. I did some research about Britain's refusal to sell Chieftains to Israel in 1969. I came across a DOD file in the National Archive, KEW, which tells about Israel's request for the 110mm gun in 1970 and 1971.
The FO refused to sell the gun as well. The file states that (in 1970) 3m Pounds Sterling (36m Pounds Sterling in today's money) were needed for the completion of the R and D.
Does the story make any sense?

3. In 1970 General Israel Tal, the Merkava's father, had a bright idea: Britain will complete the development of the 110mm gun, Israel will develop a 110mm HEAT round and then both partners will start upgrading the many thousands of tanks which packed the L7 and M68 guns. The British FO killed TAl's vision.

Thanks again.
Saul
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#10 Old ROF

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Posted 12 June 2011 - 0650 AM

..... How different were the breeches?

Stuart the 110m EXP-7 and EXP-8 ordnance both utilised the existing 105mm L7 breech (not bad considering this started out as the 20-Pdr system).

The 110mm EXP-14 ordnance had a completely new breech designed and made specifically to suit the new weapon performance requirements. Here it is being used on a slave ordnance system mounted in a chieftain cradle and recoil system. (hope this works!)

As you can see it has a vertically opening block instead of the sideways opening block of the L7 ordnance.

Edited by Old ROF, 12 June 2011 - 0651 AM.

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#11 commander

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Posted 12 June 2011 - 0829 AM

Best description yet from an actual user of the gun

When I was at Kirk we had a Chieftain with a 110mm fitted. It used two piece ammunition - projectile and a combustible case that had a brass stub cartridge on the end. All that was left after firing was the stub case with a long primer in it - about same length as 105mm primer. I actually had the stub case for some years, I gave it away about two years ago. I could probably get him to photograph it for me.

We were doing toxicity trials prior to live firing and I believe the gun was eventually entered into the American competition to source a new gun for M1. As you know they didn't choose it. By all accounts it was very accurate and quite effective. We just fired flat head proofs but I remember how effortless it was to initially open the breech, had like a fold out opening lever that you could operate with one hand.

I last saw the gun at Lulworth in the eighties, it was in the plate room at the end of the CIM building. I think the tank museum may now have it.
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#12 commander

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Posted 12 June 2011 - 0832 AM

Old ROF, yes TM= tank Museum, may have a shot but in general appearnace it is like the L30 barrel and Fume extractor etc, block is split type and on top it has if my memeory serves me X 30.
Smooth Bore my Chieftain had 120mm smooth bore fitted in the 70's

If you have any info on the MBT 80 requirements/ pictures would be very grateful as it forms a chunk of my CR2 book for the development stages. I see in the records that it was veru"well we might fit this and we might fit that " or then again nothing. Currently working with tPM of MBT 80 project to bring it to life.

Edited by commander, 12 June 2011 - 0836 AM.

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#13 Old ROF

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Posted 12 June 2011 - 1007 AM

Old ROF, yes TM= tank Museum, may have a shot but in general appearnace it is like the L30 barrel and Fume extractor etc, block is split type and on top it has if my memeory serves me X 30.
Smooth Bore my Chieftain had 120mm smooth bore fitted in the 70's

If you have any info on the MBT 80 requirements/ pictures would be very grateful as it forms a chunk of my CR2 book for the development stages. I see in the records that it was veru"well we might fit this and we might fit that " or then again nothing. Currently working with tPM of MBT 80 project to bring it to life.


Re TM gun: This could be one of two possibilities. a)This is an early production CHARM gun which had the designation XL30E1; or b)It could be a rare RARDE EXP-30 ordnance which was an interim prototype design generated after the work done for the XM1(EXP-19M13) and MBT80(EXP-28) programs and before starting the CHIP/CHARM(EXP-32) program.

Re MBT80: Unfortunately I don't have any information on the overall MBT80 program. As you may have gathered my background is on the manufacturing side and working with RARDE on production of the weapons.

I do know that the mounting arrangement intended for MBT-80 by FVRDE/MVEE was different from that used on the Chieftain & L11, which caused major changes to the breech as the SA system was located underneath rather than to the side of the gun. Only other point is that it was forward removal for the barrel rather than the rearward removal used on Chieftain.

Sorry I can't help more.
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#14 commander

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Posted 12 June 2011 - 1242 PM

Re TM gun: This could be one of two possibilities. a)This is an early production CHARM gun which had the designation XL30E1; or b)It could be a rare RARDE EXP-30 ordnance which was an interim prototype design generated after the work done for the XM1(EXP-19M13) and MBT80(EXP-28) programs and before starting the CHIP/CHARM(EXP-32) program.

Re MBT80: Unfortunately I don't have any information on the overall MBT80 program. As you may have gathered my background is on the manufacturing side and working with RARDE on production of the weapons.

I do know that the mounting arrangement intended for MBT-80 by FVRDE/MVEE was different from that used on the Chieftain & L11, which caused major changes to the breech as the SA system was located underneath rather than to the side of the gun. Only other point is that it was forward removal for the barrel rather than the rearward removal used on Chieftain.

Sorry I can't help more.



Thats fine, 2 little snippets there all help build the big picture.
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#15 Przezdzieblo

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Posted 12 June 2011 - 1358 PM

AFAIK requirements for MBT-80 were initially based on some as Anglo-German FMBT. From the start it was planned to be immune of 125 mm APFSDS projos (if remember correctly - at 1000 m) and 130 mm ATGMs. During development level of enemy projos penetration changed (from 430 to 540 mm RHA), but it was still 125 mm. Tank should not fit in MLC 60, best protected variants would be around 62 tonnes (metric). Do not know if any prototype was ever completed. There are pictures of automotive and fire control rigs. Also, few details about FCS are available, some here --> click.

Re MBT-80 gun, EXP-28M1 was significantly shorter than L11, but length of cradle was about doubled. Got a pic of this gun that is lying in some corner of TM, unforunately the presence of wall made not chance of photographing it right from behind.
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#16 Old ROF

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Posted 12 June 2011 - 1538 PM

As I understand it the reason for the longer cradle was that the forward bearing was carried on the barrel and ran in the cradle housing rather than having a fixed bearing in the cradle as used on the Chieftain, and hence had to allow for the recoil length within the cradle. Would be interested in seeing the picture of the ordnance, I really must try to get down south and visit the TM again.

Commander: At the BOCN website they have some images of 110mm ammunition, so if you can get some photos of the stub case I'm sure they would appreciate seeing them. The link is here: http://www.bocn.co.u...apds-tank-round
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#17 commander

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Posted 12 June 2011 - 1638 PM

Stub case being worked on Prez I have most of the work on MBT 80, it was not tied to any UK/FRG project, that was its predecessor FMBT, it was designed to be within the 60 bridge limit or just under BUT for combat it would have add on armour arrays that would take it well over the limit but would provide enhnaced protection similar to CR @60 tonnes. There are no photos of any rigs of MBT 80 as none were built. What has been described by the tank museum as MBT 80 is simply a mobile test rig, one of 2. They were built from parts from Chieftain and FV4030/3 project and although the ATR2 may have reembled what ight have been it ca not be taken as 100% it was to be used to trial ideas that MIGHT be used on MBT80. What does survive is one of the sights and a turret demonstrator but again not the true shape. The optics to be used have been described as the finest anywere at that time.

When cancelled the drawings were far from in a working condition, and in this research I an very lucky to be working with the MBT80 project Manager. This is an awful lot more but space precludes it + I shall use it for my CR2 book.
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#18 DB

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Posted 12 June 2011 - 1727 PM

[snip]
I shall use it for my CR2 book.

this is the best news I've heard in a long time :D
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#19 Harry

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Posted 16 June 2011 - 1030 AM

...

When cancelled the drawings were far from in a working condition, and in this research I an very lucky to be working with the MBT80 project Manager. This is an awful lot more but space precludes it + I shall use it for my CR2 book.

Same can we say about the Future Main Battle Tank (FMBT)/KPz3 Anglo-German FMBT project (1971-1977)? None were built only test rigs? And finally leads to the Challenger 1 MBT?

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#20 commander

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Posted 16 June 2011 - 1721 PM

Dead right Stu, both Nations buit "demonstrators" to explore various concept, one we missed out one was the idea of being able to use another nations power pack as proved in Jagdchieftain.
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