Incident at Castle Martin 14-06-2017

It makes me think of the trials run on Sherman's during the war which found survivability was linked to poor cleanliness and storage within the fighting compartment etc. I assume our drills today regarding ammunition storage can be traced back to this combat experience.
 
It makes me think of the trials run on Sherman's during the war which found survivability was linked to poor cleanliness and storage within the fighting compartment etc. I assume our drills today regarding ammunition storage can be traced back to this combat experience.
Partly..

..but the main reason is that guns with a bag charge cartridge are inherently more at risk from flash than a fully cased system. WW2 tanks all used brass fixed cartridge rounds as did the Centurion. The Conquerer also used a brass cartridge case, but with a separate projectile as a fixed 120 round was too large to handle in the turret.

The Chieftain introduced the Bag charge breech loading gun, initially with a cloth charge bag. The advantage was that the ammunition was smaller and lighter to manhandle in the turret and there was no empty case to fume out the vehicle. The cloth bag was replaced latterly with a combustible rigid case that is easier to handle and more robust. It was also found that combustible charge cases also lead to a longer barrel life..

Bag charge systems have been used since the dawn of gunnery, but the Chieftain was the first to use it in an AFV with a sliding breech block. The 165 AVRE gun is also BL, but it used a more conventional screw breech.

Bag charge systems have always been more dangerous and vulnerable, particularly in enclosed spaces.
 
My point is that the enquiry seems to have come down on the side of "equipment design fault" as the cause, when in fact the incident was the direct result of the equipment not being prepared or inspected correctly..

I would be interested to know of any other BL breech mechanism that prevents the gun being fired as a result of a missing component.. I know the old Chieftain breech ( I forget the L number) had a blow out pin that stopped the breech closing if there was an excessive gas leak on the first obturating ring, but this was because this could happen during normal use and had an override facility if needed. It would not AFAIK, prevent the breech closing or the gun firing if the obturator was not actually fitted...!

Guns are by definition, dangerous, pressure bearing bits of equipment. You are meant to do function checks before firing on all types of weapon to ensure they are fit for use. We are at least three or four generations away from QF tank gunnery and one would expect the function of the BL MBT armament to be well understood.

Obviously not..!

My worry is that attention will now swing towards a hardware based solution to this specific issue, which will no doubt come up with an elegant (and probably extremely expensive!) solution. What concerns me is that it will not actually address the real problem which is more to do with people rather than equipment, and in the turret rather than with the chain of command.

This tragic incident may just get through the thick skulls of those who have allowed their professionalism to slide, and act as a marker for the future! Whatever the learned Coroner thinks, or says, this should never have happened, and we all know that the Emperor got paid this time...!

Don't let it happen again.. never ever forget that living is optional!
If "cracks" (so to speak) appear in the image of the war winning rifled 120mm main armament, will it ease the acceptance of smooth bore 120mm versions made elsewhere?
Not calling conspiracy, just highlighting where procurement could spin a positive out of bad news
 
Not disputing that but I bet that was a CoC decision
Don't know, wasn't there, but my point is sometimes you risk a bit of safety on Ops if the alternative is being slower (and potentially being more at risk)
 
I would be interested to know of any other BL breech mechanism that prevents the gun being fired as a result of a missing component.. I know the old Chieftain breech ( I forget the L number) had a blow out pin that stopped the breech closing if there was an excessive gas leak on the first obturating ring, but this was because this could happen during normal use and had an override facility if needed. It would not AFAIK, prevent the breech closing or the gun firing if the obturator was not actually fitted...!
Yes mate Chieftain was a completely different breech ring and related components but just to clarify the safety aspect;

IIRC in the event of the first obturator face seal failing, the indicator pin located at 12 o'clock popped out and as the breech block dropped open whilst on run out of the gun, the pin snapped open the safety indicating device on the top of the block...

so that whilst the gun is now ready to be checked for clear prior to loading, the safety device has now dropped due to gravity, clearly indicating primary seal failure and barring the ability to load a projectile. and only a fool would reach over and snap the indicator back in position without examining the obturator, right?!

Anyway, that was Chiefy and just different but it was interesting going through the brain library wasn't it :) thanks.
 
@Swamp_Rat, assuming the experimental L30 CHARM gun you worked on and the in service L30 on mounted on CR2 are the same, how would you have envisaged the firing sequence of the gun working given the absence of the BVA? Your description seems to indicate that the vent tube is fed into the rear of the BVA so in its absence what happens, and how are the firing circuits made? Or is the BVA not used in the manner i am imagining.

I have scoured the internet for illustrations and or videos showing the various components and loading sequences with no luck.
The experimental gun was only fired remotely and I would imagine there were (had to be) considerable improvements by the time it went into service. But after considering it all day, I was trying to recall that if in the instance an obturator seal wasn't fitted, then the BVA would be able to slide rearwards (about 30mm) until the rear face of the BVA contacted the front face of the upper breech block.

If the BVA wasn't fitted then as you correctly suggest, there would be no means of firing the weapon. Because in a servicable weapon, the vent tube is loaded into the vent tube chamber at the rear of the BVA.

This is recollecting from 35 years ago, maybe someone would like to enlighten us on the current procedure. I loved my job because I like how things work, especially big guns. How everything can only work because of a logical sequence of events, it's a delight to watch. Two instances it doesn't work is when a component fails or an operator error occurs. So after wrestling with the moral and philosophical dilemma of suggesting either, I consider it would be wiser and more compassionate to walk away.

Much respect.
 

Sarastro

LE
Kit Reviewer
Book Reviewer
The yanks have very strange drills, as anyone will attest if they have experienced the US Marines CQB drills from the 90's "I'm the rabbit, I'm the rabbit, long wall, long wall" as he leads a caterpillar of 6 guys into the house. Thank fvck bad guys don't use grenades.
Language aside, that actually sounds very similar to the gold standard of CQB drills today...after a lot of operational trial and error.

The old British drills, such as I was taught in the mid 2000's at least, with two guys clearing the whole house one room each at a time, and the break-in basically just a mad rush to get in any opening as fast as possible, were obviously dogshit and more suited to police with a low expectation of anyone in the house carrying a firearm, than clearing buildings of enemy fighters.
 
The experimental gun was only fired remotely and I would imagine there were (had to be) considerable improvements by the time it went into service. But after considering it all day, I was trying to recall that if in the instance an obturator seal wasn't fitted, then the BVA would be able to slide rearwards (about 30mm) until the rear face of the BVA contacted the front face of the upper breech block.

If the BVA wasn't fitted then as you correctly suggest, there would be no means of firing the weapon. Because in a servicable weapon, the vent tube is loaded into the vent tube chamber at the rear of the BVA.

This is recollecting from 35 years ago, maybe someone would like to enlighten us on the current procedure. I loved my job because I like how things work, especially big guns. How everything can only work because of a logical sequence of events, it's a delight to watch. Two instances it doesn't work is when a component fails or an operator error occurs. So after wrestling with the moral and philosophical dilemma of suggesting either, I consider it would be wiser and more compassionate to walk away.

Much respect.
Oh I think the BVA was fitted.. I suspect it was the sealing ring behind it that was not...!

There are two basic designs of artillery gun breech.. sliding/wedge blocks and screwed breech. The Armstrong design, which was the first widely used system used a sliding wedge block (although it was tightened with a screw..). This design failed as it was poor at forming a seal between the face of the sliding block and the end of the breech. Despite Armstrong's attempts to perfect a sliding gas seal, it was not successful, particularly in turreted or Barbette mountings where a gas leak could be fatal. The Navy actually went back to muzzle loaders for a time as a result..

The first successful breech loading design was based on using an interrupted screw breech block and the mushroom shaped axial "De Bange" pad. The pad set back under breech pressure and expanded a circular seal that made the breech gas tight. The clever bit was that the heat and flames were kept away from the seal which was on the side of the block. This breech design is still used in all sorts of Artillery to this day, however it is expensive and complicated to make. The other aspect of this breech type is that the breech block sweeps in a large arc to the side of the breech when it opens. This is ok in a field gun, but is a PITA to a turret designer.. the M109 has a huge turret to accommodate the swinging block. The key to all these designs was however the seal in the breech mechanism which stopped the gas coming rearwards..

By the beginning of the 20th C they had worked out the science and magic of deep drawing metal, and were able to produce long, seamless cups that could be used to make cartridge cases. Not only the cup hold the propellant, but also by expanding against the breech, sealed the gas in the chamber. The great advantage was that there was a new seal for each shot and that a much simpler, non sealing breech mechanism could be used. This system was so much quicker to use than the old Breech Loading (BL) system it was called "Quick Firing" or "QF". Although there are screw QF guns (the 13pdr for instance) the most popular design became the transverse sliding block, which was compact and easy to manufacture. The down side however is the cartridge case, which makes the ammunition heavier and bulkier.

The original Chieftain breech was an attempt to revive the Armstrong design, using a sliding block, but incorporating a modern obturating seal on the end of the barrel and the face of the block. This is not an easy trick to pull off, and the Chieftain design just about does it.. It was however never that successful as Armstrong found out in the 1880s! A single thread hanging down from a bag charge across the sealing faces was enough to start a failure, hence the double seal and the blow out pin etc..

The CHARM gun design is an attempt to fuse the two systems. The breech has a double wedge design that incorporates a De Bange pad in the upper block that is cammed back and forward into the breech by a lower wedge block. This moves the sealing faces away from the sliding face of the block and which get expanded by the Bolt Vent Axial as it sets back under breech pressure. I suspect it was the expanding seal between the BVA and the upper block that was missing.. but I am only speculating..

The Americans have gone down another route, and followed a modified QF design, originally designed by Krupp and widely used by the Russians. This is to use a stub case instead of a full length case and make the remainder of the cartridge combustible. A problem with this design is that any scratches or dents on the stub case could lead to a failure of obturation as there is only a short length of case to provide a seal.. It does however produce a supply of ready to use ash trays..
 
Yes, but my point is it is a Command decision, properly staffed, not someone making decisions on the fly.
Sometimes commanders aren't around. Either way sometimes on Ops drills are ignored.
 
And if they go right people get medals.
Probably at the cost of other people's unnecessary loss of life. That's not the point I am making which is if it is acceptable it should be written into Doctrine and Trained for.

Just like the ROE general permission for such decisions should be documented, published and disseminated.
 
And if they go wrong people get free funerals or criminal records
Maybe, maybe not. Have you heard of anyone cutting corners in the face of enemy action that has been charged recently? Honest belief and all that good stuff.
I'm sure there have been funerals for those who followed the rule book instead of doing what they thought was best as well.
 
Maybe, maybe not. Have you heard of anyone cutting corners in the face of enemy action that has been charged recently? Honest belief and all that good stuff.
I'm sure there have been funerals for those who followed the rule book instead of doing what they thought was best as well.
You are missing my point see post #515
 
You are missing my point see post #515
I'm not missing the point. What commander wants to put his name to that? If it come to following the rules and there is a 90% chance of snuffing it compared to a known risk that has a 60% chance of snuffing it soldiers arent going to wait until they get direction from above.
 
I'm not missing the point. What commander wants to put his name to that? If it come to following the rules and there is a 90% chance of snuffing it compared to a known risk that has a 60% chance of snuffing it soldiers arent going to wait until they get direction from above.
Oh yes you are.

Where do you get your percentages from?

If a Commander does not want to put his name to it, why not? (I think you will find that is the crux of the argument)

Could 'sharp practice' on ops seep back into the training environment? That might be the case with the Castlemartin incident.
 

Similar threads

Latest Threads

Top