Primer crimps - when and why?


#1

WHEN,WHERE AND WHY DID PRIMER CRIMPING START FOR SMALL ARMS AMMUNITION ?


#2

On “WHY”:

To fasten the primer in general, to keep it in position while firing, to resist higher gas pressures and one case I know where primers were heavily crimped because the primer pocket was oversized and the manufacturer did not want to scrap the cases.


#3

I believe crimped primers started at the same time as semi and full automatic weapons, especially machine guns. Most MGs are notorious for excessive headspace and primers would pop out and gum up the works. That’s my SWAG and I’m sticking with it.

Ray


#4

Well, that I called an interesting quistion.
To be honest, I never though about that, and I also found nothing in written so far.
Perhaps I can help with a time period on M88 ammo.
The Ingolstadt production from December 1891 have no primer crimp. The head stamp from December 1892 have primer crimping.

Ray, these cartridges were made for rifle shooting only.

Rgds,
Dutch


#5

Page 244 of the “Textbook of Small Arms 1929” has the following paragraphs:

Caps come out of the case when they are a loose fit in the cap chamber, but it has now been the practice for some time to rivet all caps in place, and where this is properly done caps practically never come out.
It is particularly undesireable that caps should come out in machine guns, especially in the Hotchkiss gun, as the loose caps are liable to get into and damage the mechanism. Unfortunately cartridges are more prone to develop this fault in the Hotchkiss gun than in any other weapon, owing to the fact that the after part of the cartridge case is not well supported, and if the case is at all soft it tends to expand under the pressure of firing and the cap is thus loosened.

In testing ammunition for Casualty Proof, a Hotchkiss gun, with new barrel and long striker protrusion was used to test for pierced caps, blow-backs and caps out.

gravelbelly


#6

Excellent BUT as seen from the preceeding post by DUTCH it started well before 1929 and it looks like well before the machinegun was in use. It makes all the sense in the world to crimp primers for machineguns BUT why for rifles in the first place ?


#7

[quote=“Dutch”]Well, that I called an interesting quistion.
To be honest, I never though about that, and I also found nothing in written so far.
Perhaps I can help with a time period on M88 ammo.
The Ingolstadt production from December 1891 have no primer crimp. The head stamp from December 1892 have primer crimping.

Ray, these cartridges were made for rifle shooting only.

Rgds,
Dutch

[/quote]

Could the 92 be a reload ?


#8

I believe the Maxim MG was first issued and used in 1891 so the 1891/92 time frame for the first crimped in primers follows just as certain as spring follows winter.

As far as using the crimp to secure a primer in a grossly oversize primer pocket, it would seem odd that there would be a sudden lapse in manufacturing quality around that same time. There was no need to crimp primers before that time. So what happened to change that?

Since the United States had few MGs prior to WW I it would seem that most early 30-06 ammunition would not have crimps. I don’t have a big collection of pre WW I cartridges but those that I do have do not have crimped in primers. Are mine typical?

Ray


#9

@ CSAEOD,

This is not a reloaded round. Have also examples from Spandau.
If a M88 case was reloaded, they were used to make blanks of them.
They don


#10

[quote=“Ray Meketa”]I believe the Maxim MG was first issued and used in 1891 so the 1891/92 time frame for the first crimped in primers follows just as certain as spring follows winter.

“The Maxim guns were out and about during the Mid-1880s firing a variety of shells none of which were primer crimped”. added by CSAEOD.

As far as using the crimp to secure a primer in a grossly oversize primer pocket, it would seem odd that there would be a sudden lapse in manufacturing quality around that same time. There was no need to crimp primers before that time. So what happened to change that?

Since the United States had few MGs prior to WW I it would seem that most early 30-06 ammunition would not have crimps. I don’t have a big collection of pre WW I cartridges but those that I do have do not have crimped in primers. Are mine typical?

Ray[/quote]The owner of these rounds says that they are both RIFLE rounds. How he would know that we need to inquire. HOWEVER assignment of the primer crimp to auto weapons has the problem of ammunition made both for MG and RIFLE both of which can be found with or without crimps. In additon the 11mm Gras and 11mmVickers caliber MG shell were not primer crimped nor were the early British 577/.450 chambered Mgs nor a variety of the turn of the century MG adopted or experimental shells crimped.

If there is a critical reason for primer crimping it should be consistent over manufacturing protocals.

According to Clinton Ezell (late curator of arms-Smithsonian Institution) Germany adopted the Maxim gun in 1899 and started making them in 1908. fact is there were Maxim , Gardner and Gatling " machineguns " eating up ammunition for quite some time before primer crimped ammo is known from existing specimens.

IN FACT THE .45 MAXIM CARTRIDGE IS NOT PRIMER CRIMPED.

According to Labbett the Maxim gun was fired fired in England in 1884.
England adopted the MAXIM gun in 1889 in both 577/450 and 303 calibers. The gun was adopted in the GG case ( Gardner Gatling ) in 1892. None of the ammunition has primer crimps. The .45 guns were made through 1899. None of this ammo has primer crimps.
Back to the question: where,when and why ?

Does this help ? The .5 Vickers semi-rim aircraftMG ammo made well into the late 1930s: the British production ammo does have a ring primer crimp. The Italian production of the same ammo for the same gun DOE NOT have any primer crimp !

Pressure? The typical German 13mm Antitank and MG cartridge ( TUF ) cartridge dates in 1918 is not primer crimped. Auto gun and pressure.

Darn confusing isn’t it ?

NOTE WELL
No one has answered this question: where,when and why did headstamping start yet.


#11

[quote=“CSAEOD”]Darn confusing isn’t it ?

NOTE WELL
No one has answered this question: where,when and why did headstamping start yet.[/quote]

CSAEOD

I have a strong suspicion that we will never find an asnwer. Taking the example of the Maxim MG alone, Hiram Maxim was an equal opportunity gun maker who travelled the world trying to sell his invention to any country or individual with the cash. It can be found in a wide variety of calibers. Each nation had it’s own bureaucrats, dictators, autocrats, generals, royaltys, etc with their own preferences and ideas. Most probably not too well informed. So it’s not surprising to me that we can find all sorts of things not fitting any particular pattern. And things haven’t changed much in the last 120 years.

Ray


#12

[quote=“Ray Meketa”]I believe crimped primers started at the same time as semi and full automatic weapons, especially machine guns. Most MGs are notorious for excessive headspace and primers would pop out and gum up the works. That’s my SWAG and I’m sticking with it.

Ray[/quote]

I think that the autoloading guns and the increased pressures of semi-smokeless and then smokeless powders kicked it off but I am still looking for the earliest actual specimen with a date.

The important factor of having a specimen collection is that you see what actually was manufactured not just what was intended or written about.


#13

[quote=“Ray Meketa”][quote=“CSAEOD”]Darn confusing isn’t it ?

NOTE WELL
No one has answered this question: where,when and why did headstamping start yet.[/quote]

CSAEOD

I have a strong suspicion that we will never find an asnwer. Taking the example of the Maxim MG alone, Hiram Maxim was an equal opportunity gun maker who travelled the world trying to sell his invention to any country or individual with the cash. It can be found in a wide variety of calibers. Each nation had it’s own bureaucrats, dictators, autocrats, generals, royaltys, etc with their own preferences and ideas. Most probably not too well informed. So it’s not surprising to me that we can find all sorts of things not fitting any particular pattern. And things haven’t changed much in the last 120 years.

Ray[/quote] The technical details of ammo design is not usually related to politics. Adoption of guns and ammo types can be very much related. Primer crimping was the result of a technical NEED.


#14

Here’s a page out of the Whelen book: “Small Arms Design and Ballistics” 1945.
[/img]
Well, it didn’t come thru as well as I’d hoped, but basically, it says the crimped primer originated in WW1, to prevent the displaced primer from muckin’ up the works of an MG. No reference as to who did it first or a specific date. The drawing of the 3rd headstamp from the right reads: U.S.C. Co. / 18. There’s a start date for openers.


#15

THE RING CRIMPED USC 18 30-06 FOR AIRCRAFT MG IS WELL KNOWN . THAT IS 1918. THE GERMAN 7.9 shown is dated 1891.


#16

Italy had initial problems with Rifle ammo in the M1891 Carcano system of rifles and carbines. The porimers tended to back out and also the primer Pockets would leak. By 1895, they had resolved this problem, not by a crimp, but by a circular groove in the case head, the inner rim of this groove would “Roll over” on the intitial rearward thrust of the case on firing, this effectively “crimping” the primer in Place. When Italy adopted MGs in 6,5mm, no other crimping was found to be necessary (Italy’s first 6,5mm MG was the Vickers Light model 1906, followeds by the Revelli of 1914.)

The Germans whilst they had adopted the Maxim in 1899 and 1900, only made their own in 1908. They had bought some in 11mmM71/84 from Maxim prior to that.

The appearance of the Stab crimps in the 1891 Ingolstadt cartridge can signify several things…it was a response to firing problems in the Gew88 rifle ( Der “Juden-Flinte” affair) or experimental work by ingolstadt, which was the “Haupt-laboratorium” ( premier Research works for ammunition) or a comnbination of these.
Cartridge metallurgy was still at an early stage, and the “softness” of case heads was still unchartered territory. making the case of different hardness levbels over its length was not fully developed until the middle of the First World War ( the Russians were the first to engage in neck and shoulder anneal, to reduce Age cracking, and applied it at their US contractors, WCC, in 1916…the US Gov’t only applied it well into the 1920s.)
The Italians, in solving their Case failure problems, hardened the head by extra cold working (the circular groove).
Admittedly, the crimping of balle D ( for the Hotchlkiss M1897 Gun) was a necessary matter; but the french also developed the "protected primer ( double cup thickness, effectively a small primer ( about .200) inside a larger cup (.250); this solved the primer piercing problem of the Hotchkiss, whilst the crimp stoped the lose cups in the mechanism.

The British began ringing their .303 in 1915-16, when it was found that loose primer cups could jam Airborne Lewis and Vickers guns ( and the MarkI Hotchkiss); this also led to the use of “Flat” primers instead of the formed “Domed” style cup, for better crimp seal and application

The US so-called" Ring" crimp, is a misnomer (AN Ammo, USCCo 1918…as there exist examples of this ammo both stab crimped and non-stabbed.
The “Ringed head” remained a feature of “AN” type ammo for Aircraft MG use till 1941, whence it was dropped as of little use ( all other .30/06 was already securely “full round crimped”. The last “Ring headed” .30/06 was the Remington Arms RAF contract “RA 1941 .300z”.

The European nations continued making ammo with three stab crimps, following German practice, although a lot of countries used no crimp at all, just a tight interference fit of primer cup with primer Pocket ( usually the pocket is about .002 smaller than the primer diameter)

The Japanese, in the late 1920s, did adopt the British full circle pressed crimp for all its MG ammo in larger calibres, from 7,7 upwards;They had adopted a three stab crimp in their type 30 ammo when used in the Hotchkiss M1905 gun (Type 38), as mentioned as an inbuilt Hotchkiss problem; But in a strange twist, their locally made 7,9 Aircraft MG ammo (Type 98 7,9) was “three stabbed”, just like the Type 30/38 6,5 ammo ( probably to distinguish it from all the 7,7 ammo about)

Overall, it can be said that by 1916, all MG use ammo was crimped in one way or another; Rifle ammo followed suit by default, as it was easier to crimp all ammo during manufacture, than to risk mixing of different types of ammo.

Going back to the Ingolstadt Patrone 88nA, the reasoning behind the crimp probably had more to do with case head metallurgy than with MGs or headspace problems. Primers will back out of a too-soft cases even in a tight gun; The Use of smokeless Powder was a whole new ball game, in comparison with the earlier Balloonhead Cases used with Black Powder, and the metallurgy was not yet catching up.

Regards, Doc AV
AV Ballisticsa.


#17

Lots of interesting information there. My question is where,when and why the primer crimps were first used. You might note that there are no specimens of 11mm Mauser cartridges known with primer crimps even though,as you say, Germany had Maxim guns in that caliber. Also, many 7x57mm Mauser chambered MGs were made and used ammunition with primer crimps in that caliber are not common.The earliest primer crimp on a specimen shown so far here is 1891. I understand that here are earlier ones from Austria but have not seen those yet. The idea that the Italian “ring crimp” worked for their MGs but the US one did not is interesting . The implication is that US manufacturers spent time and money for 20+ years manufacturing a characteristic of their ammunition which was “of little use”. The addition of the stake crimp to the WW1 era US ammo over the ring crimp was weapon specific ( see Hackley,Woodin,Scranton vol 1- p112). Could you expand on the “Juden-Flinte affair”?

No doubt that the primer crimp was and is a usefull invention BUT who invented it? Given the propensity of manufacturers to patent EVERYTHING there should be patent papers which answer this question- Jim Sones- we miss you ! I suspect that those patent papers are in GERMAN.


#18

So far the earliest identifiable primer crimp is on 8x50R Austrian ammo dated 1888. These have the ring crimp. The earliest bar crimp so far is the 7.9x57 German 1891.

The following is information provided by Col. Frank Hackley , the last commandant of Frankford Arsenal and co-author of “History of US small arms ammunition” - 2 volumes ( in print-more to come)- Hackley , Woodin and Scranton.

First, this has to do with U.S. Military Small Arms Ammunition made at FA or one of the Ordnance Plants.

Basically, military primers are crimped for two reasons–First, to prevent a “dropped” or loose primer during insertion, usually caused by a lack of interference fit of the primer cup into the case primer pocket (because of an undersize cup or oversize pocket or both). Second, to secure the primer in the pocket during firing to prevent set-back or blown primer caused by abnormal chamber pressure and/or insufficient support for the head of the case caused by weapon design or loose headspace.

During the early black powder loadings of U.S. Military center-fire cartridges (1878-early
1890’s) the case was made to be reloaded (either in the field with basic reloading tool or in the Arsenal’s or Depots as fired returns) and crimping the primer would have complicated this process. In addition, the relatively low chamber pressure of these early rounds did not require crimping to secure the primer in the pocket.

With the introduction of smokeless powder in a bottle-necked case during the mid-1890’s (.30 Krag) blown primers became a problem but primer crimping to correct this was not introduced into production until 1917 with the .30 Model 1906 service cartridge. This was primarily caused by the widespread use of this cartridge in machine-guns which often did not adequately support the case head when fired, resulting in both displaced and blown primers. This practice has more or less prevailed for the manufacture of U.S. Military SAA until the present, except for special loadings like Match which are frequently reloaded . Over the years there have been a number of different crimp styles but the “circular” or “annular” is by far the most popular and is often difficult to detect because it displaces such a small amount of metal. It is a given that the practice of primer crimping can change the head hardness around the pocket so care must be exercised when performing this operation.

During SAA manufacture, crimping of the primer normally takes place during or right after insertion–the normal process being detect and gage of the primer pocket, primer insert, gage height, crimp and waterproofing lacquer applied. All this being performed on a special priming machine at very high rate.

In closing, it should be noted that commercial and sporting cartridges do not have a primer crimp–there are a number of reasons for this including the relatively small quantities made, not normally used in machine-guns, are often reloaded and usually do not have to be fired at temperature and climatic extremes.

                                                           Frank

#19

Pictures, I like Pictures.:)
Found this image somewhere in the web.


#20

Thanks for the photos. This double crimp ( ring and bar types) was designed for the MARLIN machinegun which provided little support to the case head and suffered from blown primers as a result.