So I've got this tank with "L11A4" marked on the gun breech...

#1
I've got some SMEs already looking into this, but thought some of the dinosaurs on here might have a clue. More eyes are always better.

Here's the breech in question.



Clearly says L11A4.
However, here's the gun attached to the breech.



Clearly says L11A5. We know only one L11A4 gun was made, but I don't know how many A4 breeches were made.

So, the two questions are:
1) Was it heard of to have a gun and breech of different generations? Did you ever have an L11A3 breech on an L11A5 gun, for example? Or was the breech usually of the same mark as the gun it was attached to?

2) If A4 breeches were relatively common (or at least, not unheard of), what were the differences, if any?

Any light that could be shed would be appreciated.

NTM
 

Guns

ADC
Moderator
Book Reviewer
#2
So I've got this tank.....

Good way to start a thread. :-D
 

JINGO

War Hero
Book Reviewer
#5
Cant help you but just looking at those pictures bought back that sulphur smell of a freshly fired round!
 
#6
After my time,but this might help.

Production Models. The basic L11 design spawned a series of production models; the L11A5 represented the major production version.
L11A1 – The initial production variant; 130 produced.
L11A2 – (then) RO Defence incorporated numerous minor changes to the base model, including a modified vent tube, an obturator sleeve protector, and a 15-hole vent tube magazine. In addition, the contractor used a stronger material in fabricating the breech ring.
L11A3 – This model incorporated additional minor changes to the breech ring.
L11A4 – This was a single piece used to evaluate an automatic loading system.
L11A5 – This was the main production model. It introduced the integral muzzle reference system and a fume extractor of smaller size and less weight. These two modifications necessitated the addition of 7.7 kilograms (16.94 lb) of weight at the breech for balance purposes
 
#7
It was more a figure of speech. I don't own the tank, it's in the Littlefield Collection here in California. Just trying to find out a bit more about it as I caught the A4 lettering when I was inside it a couple of weeks ago and it seemed odd.

NTM
 
#8
After my time,but this might help.

Production Models. The basic L11 design spawned a series of production models; the L11A5 represented the major production version.
L11A1 – The initial production variant; 130 produced.
L11A2 – (then) RO Defence incorporated numerous minor changes to the base model, including a modified vent tube, an obturator sleeve protector, and a 15-hole vent tube magazine. In addition, the contractor used a stronger material in fabricating the breech ring.
L11A3 – This model incorporated additional minor changes to the breech ring.
L11A4 – This was a single piece used to evaluate an automatic loading system.
L11A5 – This was the main production model. It introduced the integral muzzle reference system and a fume extractor of smaller size and less weight. These two modifications necessitated the addition of 7.7 kilograms (16.94 lb) of weight at the breech for balance purposes
And there, Ladies and Gentlemen, you have the reason why the 11th were the Regiment, in the middle of the last Century,who set the standard to which other Regiments aspired.
Such arcane subjects were the lingua france of the Sqn bars, Messes and the Snake Pit. Exessive drinking and fornication was frowned upon.
Made I laff, Brown'at, worth a pint at Telford.
 
#9
As brownhat has already stated (saw the same data myself on Wiki, but it does tally with Osprey Books info for the Chieftain MBT) the L11A4 its rearer than rocking horse shite, as it was a single unit made for evaluation purposes on placing a 120mm auto loader (similar to the 75mm system of the French AMX-13 light tank) into a Chieftain to reduce the crew to 3, so the gun and the Chieftain it is mounted in is a rear beast to be sure.

They never got the system to work properly and the tank was later reverted for use as a standard gun tank in service, don't know which unit got it and the wagon externally would have simply looked like a pre IFCS Mk5. But as anyone who ever served on Chieftain will tell you there really were no two wagons completely alike, all being in various states of modification until the day they left service.
 
#11
I quite agree with Hoochie,Chieftains all had a quirkiness about them, and all had minor niggles. The L11 gun went from A1 to A7,and having spent 2 years in a trials unit, I did actually see the A4 monster, so it is a real rarity.
 
#12
IIRC when i was on GST at Bovvy they had one in the workshops, infact a whole row of different breeches,a spotters table i think.
 
#16
Just from a numbering system point of view there is no particular reason why parts from the same alphabetical numeral can't be interchanged - i.e. L11A1 and L11A2 could interchnage parts in theory. The fact that the A hasn't changed and it's just the numeral at the end that has increased means that the build standard change is minor. If there had been a large change in build standard that affected safety or interoperability then it should have changed to L11B1.

So it may be "possible" that they had some bits left over from the L11A4 production (maybe they made a few spares) that they used to start the L11A5 run with....I'm not saying that is the reason here but I have seen it done.

S_R
 
#17
As of the 18th of Sept 2010 it will have been 31 years since i joined the JLR RAC at Bovington camp in Dorset, i still remember the tank park shuffle and the gunnery school, to answer your question L11-A1-A7 was at that time the serial numbering of the 120mm main gun components as per the instruction manual that went with the chieftain tank , so like everything the gun and its components would have been requested at the stores (if they actually had a spare), L11-a4 was indeed the breach block,(which when fired would recoil 30cm, toward the BV. The screw hole in the picture being for a dynamic bolt ans would have been used to secure the breach block to the roof of the tank then the gunner would raise the 120mm gun to drop the rear end so the the breach block would be clear for removal.(if that makes sense it has been a long time). in 1979 we had the coax fitted GPMG, which replaced the first 30mm ranging gun,before of course the laser rangefinder. God them were the days, the smell of cordite, and diesel in the morning, four tanks backed up with the ground sheet and the drone of the engines, the BV for the coffee, i close my eyes and see myself there once more, a thing of beauty she was to behold.
 
#18
.....in 1979 we had the coax fitted GPMG, which replaced the first 30mm ranging gun,before of course the laser rangefinder. ......
A 30mm Ranging gun, what were you in a Maus? we had a .50 browning when I first joined the Sqn I was on the only tank that had the new fangled MRS with TLS No3 Mk1, it was also missing the Ranging gun although there was a counterbalance in its place.
 
#19
As of the 18th of Sept 2010 it will have been 31 years since i joined the JLR RAC at Bovington camp in Dorset, ..................................................................

in 1979 we had the coax fitted GPMG, which replaced the first 30mm ranging gun,before of course the laser rangefinder. .
First of all congratulation NIG!! Scarletto tell him how long?

Secondly it was a .50 ranging gun and if you had been around then instead of still being attached to yer mum;s apron strings you would have had the joy of carrying the blinking think all the way from the armoury to the tank park on Active Edge and not just the key to the TLS!!!

I did one of the first TLS conversion courses at Lulworth
 
#20
RogerOut said:
First of all congratulation NIG!! Scarletto tell him how long?

Secondly it was a .50 ranging gun and if you had been around then instead of still being attached to yer mum;s apron strings you would have had the joy of carrying the blinking think all the way from the armoury to the tank park on Active Edge and not just the key to the TLS!!!

I did one of the first TLS conversion courses at Lulworth
I bet you had problems inserting the key into the Sight JT! Though they did move the key position to the Gnr's FCB for people of your stature!!!
 

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