9mmP with "Dished Base"-or other Dished Bases


#1

Jaco recently wrote me on his dished base and just posted a photo on the Forum under the WRA 9M-M thread. I’ve started a new thread because I also have a dished base round with a different headstamp and thought someone can shed light on these cartridges.

Jaco’s WRA 9M-M, as you can see below has a deep dish in the case head of the cartridge in front causing the loaded round to be shorter. Jaco described it to me as:

[quote]The (magnetic) projectile is also about 1 mm shorter in compare to my known cartridges, and the casemouth has small cracks.
The tip of the projectile has some rust.
[/quote]

The rust on the tip indicates the steel jacket material is exposed.

When I saw Jaco’s round I was reminded of a British load from H^N in 1945.


The bullet on this load is also flattened at the tip and the steel jacket is exposed. I obtained this round from Australia or NZ in the very early 1970s, and have since seen three or four of them, all H^N headstamps though I can’t tell you they were all 1945 dates. All had the exposed steel on the tip.

My round and Jaco’s were apparently part of a column of cartridges that were subjected to considerable pressure so the projectile of the bullet behind dished the primer and casehead, and the force somewhat deformed the bullet and wiped off the GM coating on the bullet tip.

Does anyone know how this may have occured or seen this on other calibers???

I have seen a number of commercial/military loading facilities, but do not recall seeing a step where loaded cartridges were lined up in a manner where a jam would create this degree of damage. Having said that, there are many different productions setups and I am very much not an expert.

Could the damage been in the boxing/packing process???

Is there some kind of quality control process where cartridges are taken from production and compressed in this fashion???

An help appreciated.

Cheers, Lew


#2

Lew - I have the identical round to your HN 9mm with the same dished base and the same instance of the copper being gone off the tip of the steel bullet jacket. Mine even has the same very small headstamp letters.

My original thought was that these could be rounds from testing to see if primers would ignite under a specific type of impact to the base of the cartridge, done at Hirwaun as part of the manufacturing and packing process of the ammunition. However, seeing the Winchester one, I am more inclined now to believe that they are a specific type of manufacturing error.

Have you sent these pictures to our friend in Lewiston, Idaho? He might recognize the problem if they are a manufacturing boo-boo. Occasionally, by the way, I like to use highly technical engineering terms like “boo-boo.”

I would send them, but don’t know how to transfer the pictures off of the Forum into a personal email. It will be easier for you to do it, since you have the pictures. No need for anyone to put insturctions on how to do it here - I probably would screw it up anyway, and the question seldom comes up.


#3

John,
I send an e-mail with the original pictures.
I do not think the ‘dish’ has been made by the tip of another cartridge, unless it was a hollow point. The middle of the primer is higher…


#4

I’m leaning towards an ‘upside down in the bullet press’ kind of situation…


#5

Jaco - I agree with you that it wasn’t done by a bullet tip. I don’t believe that I offered that as a possibility in my response.


#6

No John, you did not say that indeed.
Lew wrote:
My round and Jaco’s were apparently part of a column of cartridges that were subjected to considerable pressure so the projectile of the bullet behind dished the primer and casehead, and the force somewhat deformed the bullet and wiped off the GM coating on the bullet tip.

No offence ;-)
Jaco


#7

Jaco - no offesne taken. It is simply astonishing that since English is not the native language for so many of our good friends on this Forum, we understand each other so well. I thought perhaps you had just misinterpreted something I had said, but I should have known better. Most of you guys write English as well or better than those of us for whom it is our native language.

My only problem with Lew’s response is I’m trying to envision when in the loading process, or handling, packaging, or in firing mechnisms, that 9mm rounds are bullet nose to case head. I have not seen nearly the amount of loading equipment that I wish I had, but what I have seen has each round moved horizontally in a “train”, not vertically. I can’t think of any weapon’s feeding mechanisms for this caliber that are nose to primer - would be very dangerous. I have had lots of jams in various 9mm automatic weapon mechnisms over the years, with a fired case left in the chamber, or pushed back into a chamber by the next loaded round, and have never seen any instance where the impact was so great that it had a similar effect. I would think that such impact by another round would cause the bullet in the rear round to set back as it was happening, using up some of the “power” of the forward thrust into the primer of the round ahead of it. In a few of the jams that I described, that was the result to the loaded round. Further, in all of these jams, the loaded round behind that left in the chamber was moving forward at an upward angle, out of the magazine, so the deformation if it occured would not be so perfectly symmetrical. I have never had, of course, a jam where the casing left in the chamber was still loaded.

Like Lew, though, my experience in seeing loading machinery is not great (except for the type used by indivdual reloaders), in fact, much less than his, so I guess I cannot rule it out completely.

I just now, as an after-thought, tried the nose of a normal HN 9mm round of the same vintage and headstamp as the “dished base” one in question placed into the dished base of the deformed round. It does not match at all. The angle of the bevel caused to the primer pocket is considerably wider than the nose of the bullet, and could not have been caused by a tilted bullet as the width of the bevel is perfectly uniform around the entire circumfrence of the primer pocket. I would tend to rule that out as a possiblity, at least in the case of my round. I suppose though, that if the head is totally collapsed, and not just deformed inward, that the shape of the bevel could be different than that of the nose of a bullet. I hate to pull my round apart to look inside to see if the base of the cartridge has been pushed upward into the powder chamber at all. I may have to do that though. I will think about it.

I am much more inclined to think it must be from some sort of error or malfunction in the loading process, or else is the result of a purposeful impact test. I would lean towards the latter in the case of the HN rounds, since we have at least two of the exact same headstamp and same type of deformation, but the existence of the Winchester round leads me to believe it has something to do with the loading process. Unfortunately, I don’t know what. Since the bullet is deformed as well (seated deeper and the gilding metal gone from the tip) I would think that it would have to be something to do with the bullet seating process, but having seated literally hundreds of thousands of bullets on my own loading equipment, and believing, perhaps erroneously, that the principle is the same on high-speed manufacturing equipment of factory type, I cannot even imagaine the cause.


#8

Ok


#9

In something I discussed with Jaco separately, I should note that for me, the fact that the non-British round with the dished base is one of the “W.R.A. 9M-M” rounds muddies the waters both ways. If an accident in the loading process, both the machinery at Hirwaun and at Winchester during the WWII time period would have to have been about the same. I have no idea about that.

If some sort of test, the fact that we now know of a Winchester round with the same deformity is not an “exclusion” since the headstamp in question went to England in very big quantity during WWII. If there was some test done outside of the producing factory in England - a test separate from normanl quality-control testing, especially if it was a primer crush test (to see if a primer would explode at certain pressures applied over a wide surface of the cup, as opposed to a firing pin blow), then it is likely the British would have tested not only 9mm service ammunition of their own manufacture, but that of foreign manufacture widely in use in the British service. It also would be a test of both Berdan and Boxer primers that way.

Don’t read into this that I am advancing such a test as fact. Never heard of such tests anywhere. No documentation. Pure conjecture on my part. Just adding an after-thought note to the conjecture already advanced, much of it my own as well.

By the way, Jaco, you are dead on about my Dutch. Only recognize the word for “cartridge” when I see it. I am even forgetting my Italian and Spanish, which I once spoke poorly, but enough to get by. And, by the way, I am not so sure of my English anymore!


#10

Jaco,
I didn’t realize that your primer has a raised area in the center. Although unlike my H^N load, your’s is Boxer primed, I think this raised area eliminates the possibility of the dished base being made by the tip of another bullet.

Like John, I have never remember seeing ammunition in a manufacturing line where the rounds are bullet tip to base. All the lines I recall have the cartridges moving along standing vertically although there may be operations where they are horizontal. I know I saw a German made machine from before WW 2 in a Thai Army ammunition facility and the cartridges were rolled horizontal into a rather complex scale that identified those that were too light or too heavy. They were loading 30-06 at the time and I picked up one of the rejects that looked like a normal load.

I am becoming more convinced that the H^N dished base is the result of a test. Perhaps it was to see if a Sten bolt slamming a cartridge into a live round in the chamber would set off the round in the chamber. That is pure speculation, and I’m having a hard time figuring what type of test would also blunt the bullet ogive and expose the steel jacket. The test itself seems a bit obscure to me but I have seen worse.

Has anyone seen a similar dished base on any other loads-9mmP or some other caliber???

Cheers, Lew


#11

Lew has asked a question that identifies another point in favor of these being some kind of “9mm British use-specific test” and that is whether or not we have seen other rounds like them. I have seen hundreds of defect cartridges in surplus ammo, new boxes of commercial ammunition, and in oddities acquired from the junk boxes at factories and passing into the hands of collectors - Ihave probably a dozen or so such rounds that passed into my hands and I kept for one reason or anohter, and have had perhaps a dozen other that I didn’t, primarily because they were not auto pistol caliber. I have NEVER seen this particular deformity except on the rounds in question. That doesn’t make it impossible that it is some sort of manufacturing boo-boo.

I think Lew might be on the right track mentioning the Sten as well. I have a grievous fault in thinking (some would say I am not capable of it, and that is the fault) caused by the fact that I am not especially fond of SMGs and I love auto pistols, so I always think “Pistol” first in these matters. The Sten, as I recall from when I had one (legal DEWAT) would feed more straight line from the magazine to the chamber than do most pistols, and the bolt might have the impact to deform a case so severely. The only question then is why is the bullet type bothered at all, since there is nothing in fron of it in the chamber of any barrel except the bore it travels through? If a test, though, it would stand to resason that it would involve SMGs (Machine Carbines - isn’t that what you Brits called them?) rather than pistols, since at the time, England was not using many 9mm handguns.

I wish we could go back in time and place for some of these questions. They are so darned interesting, at least to me, and there is so little documentation left on so much of this stuff. I shouldn’t complain, though. When I started collecting, and Lew and others will remember this, there was almost no documentation on anything other than American ammo. There were no organized European collectors at the time. today, we have so many great researchers in the hobby, from North and South America, Europe, Africa, Australia/New Zealand, etc., that we have thousands of times more documentation than we did 45 years ago.


#12

A collector who is not registered on the Forum looked over these photos and offered the opinion that at least the WRA headstamped cartridge is a reload based on the grooves in the case photo and offered that the primer looked like someone tried to punch it out during the reloading process and deformed the primer.

I’ve looked my H^N over carefully with a x10 instrument and there is no evidence that the cartridge has been fired or reloaded.

Just added here to capture one more prespective.

Cheers, Lew


#13

As a reloader for 45 years, I can tell you that striations on the case can be from many things, and not simply reloading. The ones on the case could conceivably be from tight, sharp lips of a magazine, although it would have had to have been feed more than once since they are too close together to be a one-time “go” with the marks made by the lips on each side, or if these are a manufacturing defect, from whatever malfunction caused such other damage to the cartridge. They could also be from the round being feed into a scratched or gritty chamber.

Admittedly, the raised dimple in the center of the primer has the look of internal pressure from a decapping pin, and the deformation of the primer pocket might have made the primer so hard to push out that this happened instead.

As for reloading dies making the scratches, any die that would do that has been abused by reloading dirty or gritty cases in it, and most reloaders would throw it away and get a new sizing die.

What tells me that this round has not likely been reloaded (but it DOES NOT tell me that someone hasn’t pulled the bullet and tried to decap the round at some time) is the primer seal, which is the correct color for a WRA round of this headstamp, and obviously overlaps the primer cup, so it is not residue from a previous primer. In that case, it could be scratches from a reloading die, whichever die of a particular set had the decapping rod and pin, although why anyone would use a die that would do that is beyond me. I inadvertantly scratched the inside of a .44-40 die, and when I examined the first two cases out of the die after it heppend, I threw the die in the garbage and got another from RCBS.

Lew - my HN dished-base round is identical to yours. It shows no signs of reloading in any way at all. The chance that someone could do the identical damage in hand-operated equipment to two rounds of the identical headstamp, and be loading bullets of obvious British manuacture, is nil!

Still, the little bump in the center of the primer of the WRA round is interesting. I wish some of the guys who were involved with the factories, like the guys at Speer, would use this Forum and help us out on this. I still feel that if this “defect” was not a result of purposeful testing, than it has to be a product of high speed, automatic machinery, with the residual power to crush in a cartridge head so uniformly and so deeply. I would have to work real hard to do that on my RCBS press, even though it is an old A2 and has very, very powerful leverage. It is not something I could do by accident. I would stop fighting the problem long before such damage was caused, as would any competent reloader.


#14

[quote=“JohnMoss”]Admittedly, the raised dimple in the center of the primer has the look of internal pressure from a decapping pin, and the deformation of the primer pocket might have made the primer so hard to push out that this happened instead.

Still, the little bump in the center of the primer of the WRA round is interesting. I wish some of the guys who were involved with the factories, like the guys at Speer, would use this Forum and help us out on this. I still feel that if this “defect” was not a result of purposeful testing, than it has to be a product of high speed, automatic machinery, with the residual power to crush in a cartridge head so uniformly and so deeply. I would have to work real hard to do that on my RCBS press, even though it is an old A2 and has very, very powerful leverage. It is not something I could do by accident. I would stop fighting the problem long before such damage was caused, as would any competent reloader.[/quote]

John,

I just cannot buy the “base of case dished by following bullet” theory either. Long before that degree of dishing had occured the bullet would have been pushed down into the case and there would be a ring bulge around the case at the base of the bullet. Trying to decap one of the H^N cases may produce a small bump in the primer, after distorting the base of the case with the decapping pin, these are Berdan primed cases. Also, wouldn’t this degree of damage to a primer have caused it to fire.

gravelbelly


#15

Having fired many thousands of rounds from Stens & Sterlings although there were a fair few jams where the following round pushed on an unfired round in the chamber all that ever happened was that the following round had it’s bullet pushed into it’s case. I never saw a dished in round.


#16

Gravel belly and Armourer - I agree with both of you. I don’t think the damage done these cases could be done even by the heavy bolt of a Sten gun. It is too uniform, to boot. We have three or four rounds that are all identical. It would take a tremendous amount of force applied to collapse the almost solid-brass head of a 9mm case in the manner in which it has occured.

Regarding the dimple in the primer cup, that is not on the Berdan-primed HN cases, but only on the boxer-primed Winchester specimen shown on this thread.

Until someone comes forward with a thorough knowledge of the manufacturing processes of small arms ammunition, at factory level with high speed automatic loading machinery, including that of each stage of the case making, priming and loading process, I think that all we have on this cartridge is a guess and a gosh.


#17

I never thought that these cartridges had their bases dished in by a Sten, or any other type weapon. Trying to feed a cartridge into a loaded chamber may dent the base of the round in the chamber but sure would not the bullet or remove the GM coating as has happened to both the WRA and H^N loads.

The bullet being forced into a full chamber would drive the bullet back into the case and expand the unsupported case.

What ever happened to these loads was either in a purposeful test in a rig of some sort, or it is a result of something that happened in the loading process. I still have no idea which it was and I see no other realistic alternatives.


#18

Lew - I agree completely. They almost couldn’t be the result of a jam in any weapon likely chambered for this caliber. The bolts come home hard - I caught the edge of the side of my hand at the ejection port of a tommy gun once - an empty one. I was holding it and noticed the bolt back, so simply pulled the trigger to let it go forward. Since there was no mag in it, and it was a DEWAT anyway, I was holding it right around a good balance point, around the ejection port. Ouch! But, it didn’t slam hard enough to ever upset a brass base to the extreme that these are.