Confusion over Mk VII Sealant partially solved

jrhead75 said:

Same document, pg. 50, Table 5...

Non-Combustible Compositions for Laboratory Stores.

Beeswax, composition
.......................lbs. oz.
Pitch, Swedish.... 16 8
Tallow, Russian .... 4 8
Beeswax .... .... 44 0
Resin.... .... .... 36 0

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Thanks for your input, but I'm looking for the exact type of Resin, I already knew that Resin and wax were there. The Swedish pitch is interesting though.

It does appear that Beeswax makes up the greatest percentage of the compound. The "Swedish" Pitch may be the Bitumen eliment. The resin and Pitch together would give the material its black to dark brown coloring and the tallow would explain why it sometimes leaks past the wad to contaminate the propellant.
Excessive amonts of sealant introduced in manufacture would be why misfired ammo shows a large glop of the sealant rather than a simple smear around the case neck.
On several of the rifles I've detail cleaned the neck was coated thickly by a baked on residue of what I expect was this sealant forced back into the neck around the case neck.
I've had to carefully remove this deposit with a scraper made from brass tubing. If the build up is too thick this can cause excessive pressure by constricting the chamber neck not allowing the case neck to expand properly. The longer its there the harder it is to remove chamber brushes have little effect if the fouling is very old.

Knowing the exact type of resin would allow me to find the best solvent so less effort and minimise chances of damaging the chamber neck.
I've seen similar build up in Czech 7.62X25 pistols that were fired using what might be the SMG loading, and some SKS rifles.
The 7.62X25 cartridges I examined had resinous sealant leaking out of the case necks around the bullets.
Its likely that some eastern block countries that had experiance loading British ammo also used the same sealant.
The sealant used with a lower temperature propellant might lead to excessive build up.

krinko said:

I pulled several MkVII rounds apart, not counting several hundred POF in the past, looking for any bore coating compound and the photos show what I found.

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Then you've noticed the coating on the first one third of the bore on some enfields?
I suppose this is why you looked at all those rounds, looking for the source of the coating?

The POF rounds I broke down had a glob of the stuff in size about twice the size of a kitchen match head and the entire lower portion of the bullet was thickly coated.

The Dictionary of applied chemistry states that both wax and resin were added to the formula of Cordite MD as moderators to reduce temperature.

The Treatise on ammunition gives slightly different instructions for the Mk VI cartridge using more sealant and coating the lower part of the jacket.

Some other loadings of larger caliber cartridges used a thick disc of "wax" over the card wad.

Its possible that when they decided to add wax and resin to the formula they cut back on the use of the over the wad disc and extra sealant.
The wax and resin that settles out in the leade must mostly come from the propellant itself when firing those cartridges which used MD propellant.

Older marks and indifferently loaded cartridges like some POF possibly used too much sealant. Quality probably varied greatly during wartime.

Radway Green, Greenwood & Bately and Dominion

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Those seem to be the better quality loadings , are they not?
Haven't heard of Greenwood and Bately.

all showed a tiny bit of wax in the cannelure groove of the bullet.
This was loaded over an absolutely dry, plain, layered paper disc, which was laid directly on top of the Cordite.

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The card wad in the POF was fairly thick and glazed in some manner, the Teatise on ammunition calls for a glazed wad.
The wax collected from one bullet was incapable of being weighed on a powder scale with sensitivity of .1 grain.[/quote]
Not at all like those I've opened up.

Sorry I don't have the gas chromatograph going today---so this is all you get.
-----krinko

1.Headstamp
2.Down the Neck
3.layers of the paper disc
4.Bullet With Wax
5.Wax In the Scale Tray

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No problemo.

There is a Nitrocellulose component of the propellant The higher temperature of the nitroglycerine may tend to bake on residue that would otherwise be easier to remove if a single base propellant were used.

Turbulence in the gases as the volumne increases and pressure drops drives gases and accompanying oxides of nitrogen into the microscopic fissures of the surface, increasing chemical erosion by nitric acids as well as thermal erosion.
According to the Encyclopedia of Science and Technology
and the Treatise on ammunition

Solids soak up heat cooling the gases,
Dictionary of applied chemistry
if they are already baked onto the leade they have no further effect in moderating temperatures and reducing thermal damage.

Resins deposited on the leade would form an ablative shield.

Like I've said not all Cordites were created equal, use of ammunition with very different qualities produces very different patterns of wear.

Looks like those cartridges with the least sealant erode more just in front of the chamber and don't exhibit as much difference in progression of the erosion as cartridges which used greater amounts of the sealant.

Like most such discoveries the heat shielding properties of the baked on resin were not by design but by chance and discovered by observation of effects then working back to find the causation.

Using less sealant gave more erosion but in a more acceptable pattern with less fouling.
Instead of the egg shaped void Hiram maxim reported the erosion tapered the bore.

The hard black fouling that caused stoppages of the RAF machineguns, and the redesign, might have been from the moderators in the formula rather than the sealant.


So the rifles I've examined which had the pattern of erosion I spoke of were likely used mostly with pre Mk VII loadings or poorly manufactured Mk VII equivalent loadings.

As JR already noted

jrhead75 said:

Same document, pg. 50, Table 5...

Non-Combustible Compositions for Laboratory Stores.

Beeswax, composition
.......................lbs. oz.
Pitch, Swedish.... 16 8
Tallow, Russian .... 4 8
Beeswax .... .... 44 0
Resin.... .... .... 36 0

Click to expand...

The same basic formula is used to coat metal when acid etching, I've used it myself many years ago.

The built up residue would do little against corosive primer salts but would offer some protection against acid vapor wash and gas corrosion.
It would take many rounds fired to give any noticable build up.
The older Mk VI loading used somewhat more sealant

This was what someone else recently termed a Bituminous Sealant, and another on the board termed an Asphaltum, if the Swedish pitch is anything like the Spanish betún de Judea then the compound is not unlike that used by the Egyptians.

As noted the compound is both a sealant and a lubricant.
Its protective properties towards acids was well known, its value as an ablative heat shield was a beneficial side effect.

Are you claiming that you can get better accuracy than Major Reynolds could with a far less worn No.4 using freshly manufactured Mk VII ammunition?

Major Reynolds wrote of a test on a No.4 with early stages of cordite bore erosion that was very innaccurate using Mk VIIZ ammunition but described by him as extremely accurate using Mk VII ammunition getting four inch groups at 200 yards, which would be a hair less than two MOA.

Two MOA from a respected marksman using a rifle of that type and ammunition of that type during WW2 was pretty good shooting.

If not for your previous attempts to mislead readers including your bogus posting about US Navy use of Cordite as a propellant in 1957, one easily disproved by any who chose to actually read the document you linked to, I might be less inclined to believe that the thirty caliber pencil was at work rather than mythical ammunition that shoots better after forty years in storage or more than when freshly manufactured, or rifles that shoot better when worn out than when in reasonably new condition.

2C2. Smokeless powder manufacture

The smokeless powder used by the United States Navy is a uniform ether-alcohol colloid of carefully purified nitrocellulose to which is added a small quantity of diphenylamine to assist in preserving the chemical stability of the powder. The principal raw materials used in the manufacture of United States Navy smokeless powder are:

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As for the terminology question, since everyone else posting on the subject has used terminology different from that of the treatise and manuals.

Pedantic:

Like a pedant, overly concerned with formal rules and trivial points of learning; Being showy of one’s knowledge, often in a boring manner; Often used to describe a person who emphasizes his/her knowledge through the use of vocabulary; ostentatious in one’s learning; Being finicky or picky ...

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The use of the Term "Beeswax" when "Beeswax Compound" was the most descriptive term led you to assume that there were no other ingrediants in the sealant. Terms are not always fully descriptive, they often are a clipped description and can lead to confusion.

As the only useful information you finally did post points out the Cartridge went through many stages of development, and substitutions of components and improved formulas resulted in differing amounts of erosion and fouling characteristics.

From "the Gun and its Development" 1907.

Axite." — ' Axite " is the name of a powder made by Kynoch, Limited, for use
in military and sporting rifles. Besides the usual ingredients of Cordite, viz. guncotton,
cotton, nitro-glycerine, and vaseline, it contains some hydro-carbons and mineral
ingredients for the purpose of controlling the combustion and of lubricating the
barrel. It is made up in the form of a tape, to enable higher velocities to be
obtained with less pressure than is possible with strand Cordite. By keeping down
the pressure and the temperature of combustion by the addition of special
ingredients, combined with a scientific shape of the strip or tape, the erosion
of the barrel is much diminished and its life is correspondingly increased.
The lubricating effect of the slight deposit left by " Axite " has been publicly
demonstrated by firing "Cordite" cartridges alternately with "Axite" cartridges,
when it was shown that the Cordite cartridges gave a considerably higher velocity
of about 100 f.s. than when fired by themselves. The lubricant deposited in the
bore by the combustion of Axite has also a marked effect in preventing the subsequent
rusting of the barrel.

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Which confirms that the increases in additives to later formulas of Cordite Propellents resulted in an ablative layer of resins in the leade. A layer which would build up according to the number of rounds fired, as the amounts and types of additves incred the level of protection extended further down the bore.

Go back up to Krinkos photos and show me some crud or resin goop.

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Specious argument as we've already determined that not all Mk VII ammunition used the same type or amount of sealant.
The treatise on Ammunition is useful in that it proves that greater amounts of resinous sealants were used earlier on, and likely were used till the end of Mk VII ammunition production according to where the ammunition was manufactured.


PS
NO WW2 manufactured ammunition was used in WW1, a Great many collectable no.1 Rifles were used in WW1.
Due to the widespread manufacture and remanufacture of Mk VII ammunition and ammunition supplied to allies there are No.4 Rifles like my own which did end up using ammunition loaded in the manner of WW1 Ammunition Just as many WW1 rifles ended up being fired with highly errosive pre WW1 Cordite Mk I loaded ammunition..
All Cordite Loaded Ammunition is Erosive, some less than others but the erosion problem was never licked despite reformulations. All Cordite loaded Ammunition bathes the bore with Oxides of nitrogen which leads to nitric acid etching, there was never a cure for that.

The treatise on Ammunition undermined your position but you never realized it.
I never claimed to be an Expert on the subject of Cordite, but you seem to have set yourself up, in your own mind at least, to believe that you are.
Your skimming over the materials without really reading them is why you deluded yourself into cliaming that the US Navy was Using Cordite in its guns in 1957.

The subjects under discussion on this forum are vintage military rifles , rifles that deserve a modicum of respect for their age. Ammunition is like the gasoline in your car, it gets used up and is gone, but the cars engine will be damaged to a greater or lesser extent by the quality of the fuel used.
Some Milsurp ammunition if stored properly is nearly as good as the day it was made, but millions of rounds produced at the same time period have been culled and destroyed as unsafe and you could buy a box of ammo that looked fresh and clean which spent the week end in the store room of a gunshop whose circuit breaker tripped on the hottest day of the year and the nitroglycerine sweated out into the casings.
If NC propellants degrade they don't blow up battle ships.
You should read up on the chain fire sympathetic detonation tests on British ammunition cases sometime. Some pretty impressive craters.

In looking through available sources I found two other cases of Bolt Heads shattering from excessive pressures, One involved a worn No.4 rifle fired using a European manufactured Mk VIIIz type ammunition , not enough detail in that etry to been certain of the cause but the discussion there was on the effect of cordite errosion in creating a condition that resulted in excessive blowby when boat tail ammunition was later used. One No. 4 rifle with little wear had no problem other than lessened accuracy, the other shattered its bolt head and blew out its extractor. They didn't say whether the bullet had lodged in the bore or not.

The earlier the manufacture of the ammunition the greater the problem of erosion would be.
The longer the ammunition sits after its shelf life expired decades ago the more likely its been subjected to high temperatures that degrade the propellant in the most dangerous ways possible, sweating of liquid nitro glycerine.

Its Specious to pretend that no resinous neck sealant had ever been used because a number of loadings used a different sealant.
I don't doubt Krinko when he says he's opened some POF ammunition and did not find the same resious sealant, POF ammunition varies greatly in quality, from round to round much less crate to crate, though by all accounts unreliable.

Some believe bore erosion can not produce an unsafe condition, apparently because they believe excessive pressures have to burst the barrel in order to injure or kill.
The Instructions to Armorers is explicit in the condemnation of excessively worn or bulged barrels for a reason, discipline and attention to detail prevented accidents.
My suggestion that bores be examined in detail using an optical aid or bore scope stands. Examination of the mid bore is most important because fissures and cracks there are not easily visible from either muzzle or breech. Removal of all metal fouling before examining the bore is necessary in order to actually see what you are dealing with.
Better safe than sorry, and suggesting that excessive erosion is nothing to be concerned about is what the courts would call depraved indifference and criminally negligent homicide should someone take such advice and have a fatal accident.

TonyE said:

Well stated Doc. You beat me to it on a few points, namely that the waterproofing changed from a beeswax compound to the black bitumin type around 1940, and the fact that UK 7.62mm NATO rounds used the same waterproofing compound as that in .303.

Since British 7.62mm was loaded with one or another type of Rifle Neonite from the start, why did it need the so called "heat protecting resin"?

Regards
TonyE

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Didn't say it did.
Barrel life using Neonite Nitrocellous single based propellant only was reported as from 30,000 up to 50,000 rounds.
I ran across this article with input from recognized authorities only the other day while searching for some thing else. If I can find it again I'll scan and post it.
Theres some interesting information on the exact specifications of the FAL bore in british service at the time.
If theres a similar sealant used with the British NATO ammunition that might have actually added to bore life, though not a primary reason.

Bitumenous sealants have very much the same composition as the Beeswax with Swedish Pitch and resin compounds. Not sure but I think Russian Tallow is exacted from Beets rather than an animal fat.
I've used a similar material when acid etching aluminum plates.

The source of the "Resin" is what I'm most interested in, If CNSL that would explain its resistence to high temperatures.

I trust the bore shielding effect of resinous deposits either from the early lube/sealant or from the resins added to MD and later formulas is accepted.

Calgacus said:

Sir Sidney Smith the pioneering forensic pathologist found those fibre tips in the bodies of Egyptian rioters in the 1920s. It was something of an embarrassment to the authorities, who had expressed a preference for believing the rioters had shot each other with pistols, which would be eccentric behaviour even by Egyptian standards. He thought the fibre in question was paper maché, and it was certainly very like it I suppose fine wood pulp would be pretty much the same thing.

He only knew of the specification for aluminium, so he wrote to the military authorities (I don't remember which ones), expressing concern whether contractors might have short-changed them and whether there might be a danger of carrying bacteria into a wound. He eventually got back a reply saying that it had been an authorised wartime modification, and that it was due to the limited supply of aluminium, no net saving being made. They said great care was taken that the material should be sterilised in processing. So the effect should be no worse than being shot in the normal way.

The tips were usually extruded as wire from billets cast to fit the interior of a hydraulic press, into which they were put red-hot. The wire was then cut off and swaged cold into the little cone shapes, just like the lead core.

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When I sectioned one of the bullets pulled from the POF misfies I found a mass of what looked like the old brown paper towel paper compressed tightly in the tip. I'd expected to fing either Aluminum or wood.
When sawing through the tip a very rank chemical odor filled the room, I don't know what that could have been and it dispersed quickly.
When I fired one of these at a 70's era sedan door the bullet did not penetrate the door breaking up on the window glass. It was obviously meant to create a hideous wound at the expense of penetration.
After Action Photos of dead Pouchers shot by Game Warders using the .303 in India and Africa show terrific wounds.
In one photo you could see through the hole in a guys chest and a survivor, a teenager from the look of him maybe fifteen lost all the flesh from his upper arm, the bone completely exposed.
Photos of the Rifle used accompanied the article on one incident, it was a very old and well kept No.1 with a decorative and functional wrapping of Purple cord around the grip. It belonged to a legendary Indian Game Warder who'd killed dozen of poachers during his long career.

The Poachers killed were hard cases who'd killed game wardens and witnesses in the past, one shooting being payback for the ambush of warders a few days earlier.

Those Bullets of the Mk VII which have steel jackets sometimes fracture at the canelure, this is due to brittleness of the metal. Some do most don't its an occasional manufacturing defect.
Copper Jacketed bullets can also fracture at the cannelure through "work hardening" of the metal. Before Bronze was invented Copper knives were made by hammering the edges till the material became compressed an work hardened enough to take an edge.
The broken away portion of the base of the jacket can lodge in a bore. This generall only causes a bulge or ring if the next bullet telescopes into it but if other conditions such as high pressure charges or the qualities of the bullet which telescopes there can be case ruptures or fractured bolt heads. Counter intuitively a weak charge can also result in a telescoped bullet being more likely to cause a high pressure spike. I'll have to find the article on the accident I mentioned earlier to explain that better. The Witness in that case was trying to use layman's terms so the jury could understand what he was talking about. Not sure if that case went to the Supreme Court ,if it did I might be able to do a search if I can remember the exact time frame between the time of the accident and the time of trial.

PS
When looking into historical facts I've found these old sayings come in handy.
"Time is a River"
"Time is the Fire in Which We Burn"
"History is lies Agreed upon"
The last being a skeptical rendering of the more accurate "history is the story agreed upon" or words to that effect.

Time only moves us in one direction. So the ammunition manufactured after WW1 was not used during WW1, but Ammunition both manufactured during WW1 and Ammunition manufactured in the same manner were used long after WW1.
Someone , perhaps it was Doc AV mentioned that some US manufactured .303 casings were defective and cracks appeared at the shoulder, I remember seeing some .303 cartridges with cracks at the shoulder but not the headstamp.
When they investigated the wreck of the Lusitania some .303 ammunition brought up from the wreck was displayed and the cases were in excellent condition. Afer decades on the sea floor that ammunition was cleaned up and polished to look like brand new ammo. No cracks were visible. If this fluke were taken to mean that no US manufactured ammunition could ever develop case shoulder cracks then it would defy known fact, just as the fluke of finding cordite that remained stable after decades on the seafloor suggesting that Cordite can not degrade in a hazrdous manner would defy the known fact of Cordite that became unstable in a relatively short time and exploded destroying naval vessels at anchor when no enemy action was involved. It would also go against very test and safety protocol of the British Military.
The Ship Breakers near where I lived in the Seventies occasionally found hidden compartments in seized and salvaged ships containing very old weapons and ammunition which smugglers had been intent on delivering to various rebel organizations. Conditions of the cargo ranged from very good to dangerous junk. Freight containers were found to contain everything from WW1 bolt action rifles of various types to more modern assault rifles.
You never can tell what will turn up.

I've seen what appeared to be lake City headstamped .30 Carbine ammo that had berdan primers and was loaded to a much higher pressure and velocity than the standard ammunition. I'm told this was a case of counterfiet black market ammunition given a respected headstamp to fool buyers. Sort of the Khyber pass of ammunition, though apparently made in China. We used to call that stuff the product of the ledgendary "Long CranK Arsenal". Suprizingly accurate and it functioned well in a Carbine that normally jammed often using fresh and properly manufactured ammunition.

Calgacus said:

Whoever is responsible for making these boards fit for civilised technical debate, it is going to take more than you have tried so far. Looks like we are going to need this a while yet:

http://www.swordforum.com/forums/showthread.php?t=82858

There was no question of the lightweight tips in .303 bullet being designed to break up and cause more serious wounding, which would have been against the Hague and later Geneva Conventions.

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I'm talking about the POF with the black sealant.
Those bullets were most likely designed to break up.
Could be a manufacturing flaw I suppose but the lack of penetration and the consistency with which this particular batch fragmented like varmint rounds leads me to beieve it was deliberate.
The brown paper and brittle jackets just don't seem to me to have been an accident.

Oddly the same bullets punched neat mirror finished holes in thick I beam webs that looked like a laser beam had cut it.
The bullets completely vaporished and left a smear on the beam behind it.

As for the British designing the bullets they used to fragment, I'd say the original aluminum nose plug would speak against that sort of fragmentation being their goal, but I also don't think they really had an excuse to use the bullet knowing its effects.

It was to provide a longer, more pointed tip, and thus superior long-range performance to the old round-nosed bullets of greater weight. The relatively humane wounding of the latter was well documented in arms design and military surgery textbooks, but was generally hailed as a good thing with no attendent disadvantage, since wounded men continuing to fight was rarer than Hollywood would have it.

Of course the bullets did keyhole very easily, and broke up at the tip. But then so do most of the bullets in use today, with similar effects. Breakup seems to be a byproduct of keyholing after impact, and most of the catastrophic wounding would be caused by one that keyholes and remains intact.

Up till now international law has concerned itself with means, such as core exposure or jacket slitting, a bullet might be deliberately designed to expand and cause excessive wounding. There is now a Swiss draft protocol of 1994 which seems to define it by energy loss in flesh, which may yet be used to minimise much unnecessary suffering.

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Not too long ago a particular 7.62 NATO bullet manufactured in Europe was banned for less cause.
It also had a work hardened brittle jacket but was otherwise of conventional construction, If anything that bullet was less damaging than the British bullet with aluminum nose.

BTW
The bullet that broke up in the door had penetrated one sheet metal panel.
When it hit the glass it was already damaged.
The bullet fragmented into tiny beads of lead and dust. The glass and bullet fragments hit the inside door panel like a small gauge shotgun blast but few fragments made it through the padded material. The door panel was bowed inwards by several inches.

This was a heavily constructed sedan.

I'll see if I can find the bullet I sectioned, I don't think Ikept the paper but I may still have the jacket.
The metal jacket was about half as thick as I'd expected it to be.

Only living thing I shot with this ammo was a large turtle that had been killing off all the fish in the pond on the land where we were shooting the owner asked us to get rid of it.
The Turtle was about as big as a head in a helmet.
When hit the shell jumped ten feet in the air and the turtle seemed to be turned into a mist. Of course there were probably fragments of flesh and bone every where but it looked like it had been vaporised.

With copper, gilding metal and brass, the commonest reason for brittleness would be work-hardening and insufficient annealing. Cupro-nickel, however, has a tendency to become brittle from annealing at temperatures only a little excessive. Since an arsenal skimping on annealing is more likely to have it show up in the cartridge case, I think overheating is more likely than not doing it.

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Good information there, at last we are getting somewhere.

Bullet cores are usually lubricated for the swaging process, and it has to be a lubricant with a very high flash-point, due to the pressures involved in the process. Modern swagers use lanolin, a byproduct of the wool industry, which didn't exist in India. So in wartime they might have used anything, and it might have caused that smell.

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The compressed paper nose filler would soak up residual lubricant. I remember thining at the time that the filler might be impregnated with a resin binder but the paper can out in tiny strips and shreds with nothing holding it together.

The British had exactly the excuse the Americans have to use the current or previous M16 bullets, no more and no less. It was alarming, but not seen as being against the laws they had signed up to. This is debatable, as the definitive text in the agreement was the French one, in which "s'epanouissent" has more of a suggestion of any kind of spreading out, rather than just expansion. That might perhaps more reasonably have been interpreted to include breaking up, but almost everyone has chosen to interpret it differently.

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I never liked the idea of the early M16 bullets breaking up like that. The rifle wasn't intended for a long range role where the effect would be less terrible.
Probably wounds at longer ranges using the aluminum nosed bullet wouldn't have been as terrible.

Range makes a great deal of difference in penetration even when using AP.
At extreme close ranges the longer bullet is still yawing, it takes at least 50 yards to begin to stabilize. An AP bullet generally penetrates better at 200 yards than at ranges under 10 yards for this reason.

Similarly there is a letter of Churchill's on record, to the Minister of Food I think, deploring the lack of an extra sugar ration to beekeepers, since British bees require an allowance of sugar syrup to get them through the winter after most of their honey has been taken. I don't know if the bees thereupon received special consideration, but it seems likely that beeswax supplies might have been restricted in wartime, resulting in a search for other substances to mix with it.

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I figure that by WW2 they'd already decided that the excessive deposits of resins at the throat and chamber neck were making it too difficult to get the bore really clean and chose to go to a neck sealant that left less deposits. The resins added to Cordite MD were doing a better job and burning away with each shot.
Some later propellant formulas reduced erosion further but were no ready to completely replace the propellants already in use and in storage. So some ammo used the black sealant and some didn't.

I had guessed that something quite different from the glass, which alone was mentioned, broke up the bullet. I knew someone who took grave harm from an olive once. A large number of martinis without did him no harm whatever, but it was the one with the olive that did for him.

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Yeah you'd have to go through the outer sheet metal to get to the glass.
There are stamped reinforcements of even heavy and tougher steel but the bullet had not hit those.
When a bullet encounters successive layers of greatly different materials the effects are not easy to predict.

70's US Sedans are built like tanks compared to modern cars and most european cars.
Back in the early 90's some Kuwaitis came through here buying up a specific model of Chevolet to replace those Saddam's troops had stolen. Seems like it was the favorite of body guards over there. They'd asked about these at my Nieghbor's body shop offering top dollar and arranging complete overhauls and such, putting them back in showroom new condition.
I guess they were more familar with the design and had plenty of spares for that model still in stock. Probably it was a good body to armor up.

Found this book except that if correct would give an idea the sort of black market POF ammo still floating around.
Some of the POF stamped ammo may be counterfiet or assembled on scrapped cases.
http://books.google.com/books?id=M_...hl=en&sa=X&oi=book_result&resnum=10&ct=result

Cordite MD consists of Nitroglycerine, guncotton, and mineral jelly...period.

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I'll get back to this as soon as I've finished checking the types of Hydrocarbons in Vaseline and whether any of these is a Hydrocarbon Resin.
Moderation of the temperatures and slowing the expansion of gases may have had the effect of leaving a hydrocarbon resin residue that would have had the effect noted in the alternating axite and cordite experiment.

I'd been thinking of this as a matter of additives but it may be a matter of natural contaminants. Few products are anywhere near chemically pure and mineral Jelly is a mixture of many hydrocarbons. Never heard of any 100% efficiency in any explosive or propellant even theoretically.
I just don't believe any explosive or propellant can leave no residue.

PS
I finally figured out how beets are connected to Russian Tallow. Russian Tallow had some superior qualities attributed to the fodder the Russians used for their cattle , dried vetgetables, and "Fodder Beets" was the main difference.
Could be the Beets had an effect on the fat at a molecular level.

I'd like to find out the exact formula used for the Cordite in late manufacture Dominion ammunition, down to the last detail.

The lanolin sealant/lube is something else I need to look into. Lanolin is a cleansing agent, but how it reacts at high temperatures I've never heard.
Odd but Alchemists called Lanolin "Baby Boy Fat" in their coded notebooks, which got a few of them in a lot of trouble if any children disappeared nearby when they were running their experiments.

Thunderbox said:

GunnerSam,

You've constructed a series of theories based on your view that cordite is much hotter and more damaging than contemporary NC powders.

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Excuse me but the "view" that cordite is hotter and more damaging than NC powders is not a personal theory. I can't think of any authority on the subject who'd claim otherwise.

Can you quantify this? How much hotter is cordite than NC - is it 10%, 20%, 60%, 200%? I.e. what difference would be significant enough to cause accelerated erosion?

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To give you an idea the drop in operating temperature between Mk 1 and MD greatly increased barrel life, yet Cordite MD was still much hotter than any NC propelent that remained in use.
I posted thermal properties of Cordite VS contemporary single based NC powders either in this thread or the earlier one.
Theres never been a doubt cordite has worn out barrels in fewer rounds than quality NC powders in loadings of the same power levels.
The only doubts are in the observed wear patterns of bores, and factors that produced the variations in wear patterns according to specifics of ammunition and weaponry involved and methods of reducing erosion.
Its not just Cordite that had these thermal properties the early Double Based powders also eroded bores quickly , some worse than cordite,and were abandoned for anything except special purposes.

p.s. you've cut and pasted another lump of hearsay in one of the ammunition stickies. I'm not replying there, because the stickies are intended for facts - pictures, surveys, polls, etc. The PPU MkVIIIz you referred to is well known - I've fired more than 1,000 rounds of it myself. In fact the stuff had near identical ballistics to MkVII/z at all ranges, and it chrono'd in exactly the same zone as MkVII. The bullet was around 175 gn, and the only significant difference being that it had a boat-tail bullet. I.e. it was true MkVIIIz - simply MkVII/z with a different bullet, and no hot/heavy/rifle-stretching peculiarities. I would guess that the identical same round is what Privi Partizan is now retailing as "MkVIIz".

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The warning notice on the blown out extractor was something I ran across while looking into bolt head failures due to excessive pressures. Would you rather no one looked at such warnings?
It doesn't occur to you that there might be variants in manufacture or that some lots of ammunition might pose a danger?
That warning said the ammunition worked okay in a No.4 in good condition but blew out the extractor of a worn no.4.
Should prospective users who might consider using this ammunition in a No.4 with significant wear not be advised of a possible hazard?
It also suggested that the round not be used in the No.1 rifles because it can stretch the action body.
The action body of the No.1 flexs a tiny bit with even relatively mild Cordite loads otherwise there would not be an offset to the front sightbase to compensate for altered haromics.
Why overstress an action when its un necessary?
Metal fatigue effects every metal object sooner or later, no firearm is immune to the effects of time.


No I'll get back to this later.
Things to consider.
Though the majority of fouling from use of ammunition loaded with Cordite comes from the sealant the presence of harden black fouling in the end cap of aircraft guns which drasticaly effected performance shows that something else was present.
The need to alter the parent design and prototypes of the brengun to move the gas port back 9 1/2 inches was attributed to "cordite fouling".
The position of the Bren Gun gasport corresponds roughly to the hotspots I mentioned earlier. The positioning of the port suggests that this spot was chosen because there was less fouling from the propellant left there.

PS
Why would anyone choose a username that is used as slang for the Toliet or the Female private parts?

jrhead75 said:

Take it up with Cpt. Laidler, he no doubt could show you that very report. Personally, I'm willing to take his word for it.

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from the post by Laidler which is always quoted

As for the crazing problems, well, while there was crazing, and I saw some, we used a bore-scope and if 'in the opinion of the examining armourer' it was excessive, the rifle was scrapped. But I never saw a service rifle that exploded because of it! We did have a very good example of it for illustration purposes and a few cut-away barrels at Shrivenham.

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Of the two rifles that hit the headlines, the spectacular one

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There have been incidents since then involving Cadets acting like dummies or not knowing about safety issues, I found a few news stories on those but no public outcry.

As I mentioned earlier Laidler's remarks have been taken out of context in order to give the impression that Craze Cracking is a myth or that Craze Cracking can not produce an unsafe condition.
Also Laidler mentions the use of a bore scope, which I also suggested, because this sort of damage may not be visible by looking from one end or the other.

Now I have things to do.
I'll get back to this latter.
Laidler mentioned the sectioned barrels, I've seen photos of sectioned barrels illustrating the sort of localised gas erosion I mentioned, perhaps I can find a photo.
PS
The form of damage caused by thermal Gas erosion is not uniform, In most cases it wears away, but in others it leaves raised crater edges. In some areas the bore is smoothly washed away and in others little is removed but the suface is cratered, not pitted in the same was corrosion pitts steel but from high energy impact by particulates and high temperature bubbles which form from an effect similar to Cavitation in high pressure fluids. The super heated particulates and heat bubbles strike the steel like tiny meterors. The damage is microscopic at first but the effects become visible , craze cracking would not even become visible to the bore scope if not for the effects of gas erosion or chemical erossion and corrosion.

I'll get back to this when I find an online source which explains thermal/ gas erosion better than I can.