Tank gun/artillery primer tube identification


#1

I have two British artillery primer tubes recovered from the bilge under the turret basket of a Chieftian Mark 7 tank. I have seen both of these sizes before but wonder why two distinctly different calibre tubes would be in the same tank. The Chieftian has a 12omm main gun and it is possible that the type of primer may have changed by a modification of the gun.


The second query is why does the slimmer primer have a case made in two parts, of different metals? In case it is not clear in the scans, the larger headstamp is: RG 67 L1A3 EW and the smaller headstamp is: XL4E2 RG 88 24

gravelbelly


#2

I am very interested in large caliber tank ammunition and with the exception of torpedo artifacts, it is my primary collection interest. I hate to sound stupid, but what is a “Primer Tube”? They look like bullets/ shell cases to me in the photos.


#3

The larger calibre guns, without a cartridge case but using a bagged charge, needed a seperate primer to flash them off. The tube was inserted into a mini-breech usually located in the main gun breech block. The flash from the tube travelled into the gun chamber to ignite the charge. In this case the two tubes I illustrated are electrically fired. They differ from normal small arms cases in being very heavily constructed as they have to obturate the main gun pressure for a much longer time than a normal small arms case. They also sometimes incorporate a copper ball non-return valve which is blown hard into a conical seat so that the cap is not blown through.

gravelbelly


#4

I’d hazard a guess that the later date and the “x” prefix of the smaller one suggests a different, possibly experimental gun system (or even just a breech block) had been installed at some time. Were there any sub-claiber devices used with this tank? Any history on this particular vehicle that might explain this? How are the fired tubes collected? Do they eject into a basket of some sort?

AKMS


#5

Thank you Gravelbelly. I get it now. Makes perfect sence. Thanks for the explanation.


#6

[quote=“AKMS”]I’d hazard a guess that the later date and the “x” prefix of the smaller one suggests a different, possibly experimental gun system (or even just a breech block) had been installed at some time. Were there any sub-claiber devices used with this tank? Any history on this particular vehicle that might explain this? How are the fired tubes collected? Do they eject into a basket of some sort?

AKMS[/quote]

I agree that the smaller tube has what appears to be some experimental looking headstamp. This tank was at a coastal gunnery proof range for some years but saw little use so it was sold off as surplus a few years ago, in running order. This proof range tests guns, ammunition and armour plate. As to how the tubes are ejected and collected I shall have to spend some time crawling around inside it for clues, I was Navy, not a tanker. I will post two photos, one showing the tank exterior and one showing the rear of the main gun breech ring, taken through the left turret hatch.

gravelbelly


#7

Here are some, what I’m guessing to be artillery round primer type things. These were factory demo samples. Nothing like the primer/igniters for the tank gun, so I’m guessing artillery. My 5" x 54 hull has something like this, so I’d bet these are for larger rounds vs a 120MM tank gun.

That’s a .223 for comparison.

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#8

[quote=“slick rick”]Here are some, what I’m guessing to be artillery round primer type things. These were factory demo samples. Nothing like the primer/igniters for the tank gun, so I’m guessing artillery. My 5" x 54 hull has something like this, so I’d bet these are for larger rounds vs a 120MM tank gun.

Yes, those are primers but for a Quick-Fire cartridge case, not for a bagged charge gun.

gravelbelly


#9

Ah-so. The bag charges need the bullet shaped primer vs the loose powder needing the igniter tube thingy. Makes sense. What about the US 120MM? They don’t appear to use the cartridge system. Is the projectile loaded seperately in the Chieftain and then bagged charges behind it? No shell, per se?


#10

The US 120mm tank gun is a German design IIRC. It uses a semi-combustible case. The base “stub”, as it is called after firing, is steel and about 4" tall. The rest of the case is made of a combustible material. This unit is loaded just as a regular round with a full metal casing. It is not seperate or semi-fixed. In the Abrams tank there is a basket to catch the fired stubs so they don’t roll around in the turret basket like the older designs with full sized cases. Makes life a lot easier for the loader for sure as he does not have to dance around these rolling cases while trying to load another round! Also, IIRC, the HEAT round for the 120 has a long flash tube like pictured above, but the APFSDS does not due to the length of the penetrator. I think CSAEOD posted pics of these a short while ago.

From where this tank came from I’d say there is a high probability that it was a test-bed for some other gun system. Hope we can find out more!

AKMS


#11

You have two 120mm Tank Tube Vent Electric (TVE) as have been identified
the RG 67 L1A3 one is (off the top of my head) the old .625in TVE used with the L11. The other one is a little bit more rare being an experimental version of the 13mm L4 used with the current L30 gun used on Challenger 2. Of note the L4A1 was also a trial only version not being accepted into service due to beryllium in the copper of the rear portion.

why you have two non-compatible TVE in the same turret Im not sure but you may find that the Bolt Vent Axial( BVA) - the secondary breech off axis on the back of the main breech - does not marry up with the L11 gun you have in the turret and has been replaced with a trials one.

As to why a two piece construction it is an aid to assembly (as these are conducting cap initiated and slightly more complex than percussion) and also to withstand the pressures of the new L30 gun.
BTW most UK artillery tubes are parallel sided and percussion whereas tank are electric.