Firearms Technical Trivia, January 2002:

Bullet Jacket Design Principles
The 7.92x57mm Cartridge in Polish Service
Bullet Jacket Design Principles

The Second World War Begins
In the predawn hours of September 1, 1939, the German Army swept into Poland and ushered in the age of the Blitzkrieg and the Second World War.  At that moment, Poland, like the majority of small European nations, had equipped its forces with a mix of modern and obsolete weapons.  Poland's small arms were not markedly inferior, or for that matter, measurably different from their German counterparts.  Indeed, the majority of them shared the same cartridge.

Small Arms Ammunition Production in Poland
In February 1921 the Polish Ministry of Defense established the first government owned facility to produce military rifle cartridges.  The factory, which produced completed cartridges, bullets, primers, cases and ancillary items, was called Wojskowa Wytwornia Amunicji Karabinovej (WWAK), and was located in Warsaw.  The cartridge fabrication machinery had been nationalized from the holdings of the Georg Roth A.G. subsidiary formerly located in Posen (Poznan).  Production efforts were divided amongst three manufacturing divisions.  After four years of operation in Warsaw, the plant was moved to Skarzysko-Kamienna, southwest of Radom, where it was renamed "National Ammunition Manufacturing Facility."  Cartridges produced at the original WWAK factory in Warsaw were headstamped with a "W," and often the Polish eagle as well.  After the 1925 move, the headstamp contained the Polish eagle, but not the W.  After the fall of Poland in 1939, the factory was taken over by the German firm of Hugo A. Schneider, AG (HASAG), and continued to produce ammunition, albeit for a different destination.  Ammunition produced during HASAG's stewardship of the factory was initially marked with a HASAG logo, and later with the German ordnance code "kam."  HASAG used the pre-war inventory of cartridge cases in producing initial lots of mild steel cored ammunition.  Eventually five major arsenals, producing war materiel including ammunition, were to be established.  Each of these was officially identified by a numerical designation:

Arsenal Number
Arsenal Location

As the Polish treasury between the wars was in a perpetual state of fiscal crisis and the state run factories were not achieving the volume of ammunition production desired, private investment and contracting were encouraged.  As a result, a commercial organization with both Polish and French investors called Zaklady Amunicyjne, Pocisk, Spolka Akcyjna (Corporation for the Manufacture of Ammunition) was created.  This company, generally known as Pocisk SA, began to produce ammunition, using machinery purchased from Hirtenberger of Austria, in 1921.  (Pocisk means "projectile.")  The ammunition produced bore an abbreviation of Pocisk, "Pk." on its headstamp, while boxes had the abbreviation Z.A. "Pocisk" S.A stenciled on them.  By 1922, Pocisk was operating two plants, one, the Warsaw "Praga" division which made cartridge making machinery and weapon parts, and the other an ammunition plant at Rembertow, some 15km west of Warsaw.  Rembertow's production was not limited to small arms ammunition.  The plant produced components and complete cartridges, primers, explosives and artillery shells.  In 1925 the government sought to maximize Pocisk's capabilities while minimizing costs, and began a program with resulted in complete nationalization of the firm by 1932.  At the same time, all operations were transferred to the Rembertow plant.  Pocisk played a critical role in Poland's preparedness - by 1935 it was supplying over 30% of the nation's ammunition requirements.

Another important Polish ammunition manufacturer was Norblin, S.A.  Located in Warsaw, the company was established in 1922, and was a key producer of 7.9mm rifle ammunition until the invasion in 1939.  Norblin's trademark was a capital letter "N" which can be found on the headstamps of cartridges assembled by the firm.  If the cartridge was made entirely with components manufactured by Norblin, two diametrically opposed N's appeared on the headstamp.  Norblin's owners were a Mr. T. Werner and the Buch brothers, and throughout its existence it was a privately owned and funded company.  While Norblin's main plant was in Warsaw, it operated a foundry and brass mill at Glownie (near Lodz).  The Glownie facility not only supplied Norblin's needs but also provided cartridge brass to Pocisk and other government arsenals.

A Brief Overview of Polish Small Arms
The interwar Polish Army used several indigenously produced Mauser type rifles as well as the Model 91/98/25, which was a conversion of the Russian Mosin-Nagant to 7.92x57mm.  The standard Polish light machine gun was the Wz28, a modified Browning Automatic Rifle.  Heavier automatic weapons included the Maxim MG08, the Hotchkiss 14/25, and the Wz30, a type of water cooled Browning.  The Polish Air Force used a number of Vickers Armstrong designs, such as the Wz23 (a 7.92mm Lewis gun), and the "F" and "K" models.  Fixed aircraft weapons were largely 7.92mm Browning derivations.

7.92mm Polish Ammunition Overview
Polish military forces were supplied with a number of 7.92mm cartridges.  These included:

Heavy Ball
Armor Piercing
Armor Piercing Tracer
High Pressure Test

Additionally, the rifle assembly plants used several types of wzorcowy, or reference cartridges with which to test new weapons.  These cartridges were assembled using carefully chosen S or SC projectiles and components.  If a rifle, carbine, or machine gun failed to meet the required accuracy standards with these rounds, it was assumed that the gun was at fault and that a mechanical correction was in order.  These cartridges were identified by box labeling only and did not bear any special marking on the case or bullet.  The Air Force received special high grade aircraft armament ammunition in S, P, PS, and Z varieties.  This ammunition was given special consideration with respect to primer and propellant quality control.  These elements are especially critical when the ammunition is to be used in weapons synchronized to fire through the propeller arc; cartridge ignition and response time must happen in a constant, predictable manner, or the resultant damage to the propeller could literally result in the aircraft shooting itself down!

Ball Loadings
Note:  Polish documentation uses the terms 7,9mm and 7,92mm interchangeably.

Naboj kal. 7,9mm wz. 98 Szpiczasty ("S") - {Cartridge, caliber 7.9mm, Model 98, Pointed Bullet}

The standard ball cartridge, it can be recognized by a black primer annulus and pointed bullet.  Polish ammunition box labels were usually printed in the same color as the primer annulus on the cartridges found within.  For example, in this case, the markings on the box would be black.  Total weight of this round was 24.5g or 378 grains.

This was a duplication of the original German S-patrone with a 10 gram (154.3 grain) bullet, and was intended for Polish military rifles such as the K98, wz98a and wz29 Mausers.  Interestingly, many Polish service rifles were manufactured on machinery that had been originally owned by the Imperial German Arsenal at Danzig (Gdansk).  Ammunition box labels will indicate the intended use for rifles, short rifles or carbines by the following inscriptions: do kb/k or do "Kb" (Karabin).  Some labels go a step further with the inscription "Syst. Mausera" or "Nb. Mauser," with the latter imprint meaning "Cartridge, Mauser."  References like this are generic, and indicate that the box contained ammunition for Mausers, and not the Lebel, which was also in use at the time.  Average muzzle velocity 790 m/s (2,592 fps).

The typical Polish ammunition box was constructed from tan card stock measuring 85x60x30mm (3.346x2.362x1.299").  It contained three tiers of five cartridges, which were divided with two brown paper sheets whose purpose was to restrict movement and provide a cushion.  Stripper clips were made of steel or brass, with some being nickel plated as an attempt at environmental protection.  Nickel plated clips will bear a T within a triangle.  Steel stripper clips were designated Lodka wz98, and brass strippers were designated Lodka wz17.

Polish cartridge drawing, S cartridge
Polish cartridge drawing, S cartridge
When pulled from an assembled cartridge, the S bullet will often have the bullet maker's mark or monogram in relief on the exposed rear of the core.  These markings are usually "Pk" or "N," as bullets from the government arsenals were not usually marked.  The core was lead alloyed with two to three percent antimony and weighed 7.5g.  There were four official variants of jacketing material:  Unplated steel, cupronickel, cupronickel clad steel, and gilding metal clad steel.  Unplated steel bullets are believed to be of very early issue, likely made from remaining stocks of Austro-Hungarian supplies.  Both the unplated steel and gilding metal clad steel are very rarely encountered.  Bullets were crimped into the cases by a six segment collet device pressing the case mouth into the cannelure.  Polish cannelures were not sharply rolled into the jacket as the late German ones, with the exception of the Maroszek DS bullet.  The S bullet was typically 27.8mm (1.094") long and weighed 10 g (154.3 g).  It was propelled by a 3 g (46.2 grain) charge of square flake powder.  The bullet diameter was typically around 8.2mm (.322").

Primers (in Polish, splonka zapalajaca or kapiszon) used on the S cartridge were designated wz90,  weighed 0.28 g, had a height of 2.6mm (0.102"), and a diameter of 5.5mm (0.216").

The cartridge case will usually have a very revealing headstamp.  At the twelve o'clock position is the casemaker's mark; Pk for Pocisk, N for Norblin and an eagle for a government facility.  At the three o'clock position is the year of manufacture.  At the six o'clock position is a marking indicating the supplier of the cartridge brass, and at nine o'clock is a marking indicating the percentage of copper in the brass alloy, either 67% or 72%.  The 67%/33% alloy was officially adopted in May 1925.  Despite the official adoption, the earlier 72%/28% alloy shows up as late as 1937.  Experiments were made with other materials including copper and steel.  Pocisk produced a run of steel cases with a phosphated and lacquered finish in 1937 - 1938.  There are twelve known brass supplier codes, and these include B, D, DZ, E, F, Fr, Hr, K, N, NW, W and an arrow.  Of these, only three have been positively identified; N for Norblin, Fr for Fabryka Platerow Herfra (Fraget), and DZ for Dziedzice-Walcownia Metali.

Naboj kal. 7,9mm wz. 98 Szpiczasty Cieszki  ("SC") - {Cartridge, caliber 7.9mm, Model 98, Heavy Pointed Bullet}

The heavy ball cartridge can be recognized by its green primer annulus, as well as by box labels printed in green.  This cartridge is a duplication of the German s.S. ball, and indeed, some labels are marked s.S. to indicate German origin.  Early SC bullets differed from the German produced variety in that they used a cupronickel jacket.  This jacketing material was used until 1935 when cupronickel clad steel and gilding metal clad steel was introduced.  The SC round was intended for machine guns and the label marking do KM or "Karabinu Maszynowego" or machine gun.  Examination of a typical round with the cupronickel jacket reveals that the jacketing material consisted of 81.19% copper and 18.81% nickel, while the core was 97.85% lead alloyed with 2.15% antimony as a hardening agent.  Official Polish specifications for the SC cartridge indicate a total cartridge weight of 27g (416.6 grains), an overall length of 80.3mm (3.161"), a bullet weight of 12.8g (197.5 grains), a bullet length of 35mm (1.377"), a core alloyed with 2- 3% antimony that weighetd 10 g (154.3 grains).  Jacketing material could be either cupronickel, cupronickel clad steel or gilding metal clad steel.
Polish cartridge drawing, SC cartridge
Polish cartridge drawing, SC cartridge
Naboj kal. 7,9mm wz. 98 Dalekonosny ("D") - {Cartridge, caliber 7.9mm, Model 98, Long Range}
In addition to the standard S and SC ball types, a third form of ball cartridge was issued in small amounts.  Known as the D (for dalekonosny) or long range cartridge, this round was produced by Norblin and Pocisk for use in the Polish wz28 derivative of the Browning Automatic Rifle.  Its designer was T. Lukaszewski of the Military Technical Institute.  Lukaszewski's bullet featured a 5 - 8% antimony alloy lead cored bullet that weighed 13.9g (214 grains), giving the cartridge a total weight of 28g (432 grains).  The D cartridge was recognizable by its violet or dark purple primer annulus.

Naboj kal. 7,9mm wz. 98 Szpiczasty Cieszki o wzmocnionem cismen - {Cartridge, caliber 7.9mm, Model 98, Heavy Pointed Bullet with augmented pressure}
This was a high pressure test cartridge used for proofing rifle and machine gun barrels. It used the standard SC bullet, and standard components.  The only difference was the propellant, which was blended to provide the required pressure level.  A white primer annulus identified this cartridge.

Naboj kal. 7,9mm wzor Przeciwpancerny ("P") - {Cartridge, caliber 7.9mm, Armor Piercing Model}
While the Mauser rifle and its ammunition entered Polish service in the early 1920's, it wasn't until the mid 1930's that a need for an armor piercing cartridge arose.  Like the S and SC bullets, the P bullet was based on the German S-Patrone; in this case the S.m.K. armor piercing variant.  Polish documents indicate that the P bullet was originally intended solely for use by the Polish Air Force (Lotnictwo Wojskowe), and later issued to ground units. The P cartridge is identified by a red primer annulus.  Most of the P cartridges were produced with Norblin cases dated 1936.  The P bullet was produced with a steel core remarkable for its purity, comparable to US bearing steels such as AISI type 52100.  Tests for Rockwell hardness yielded a range of between 65 and 67.  The P bullet was 37.5mm (1.476") in length, weighed 11.9g (185 grains), and was propelled by a 2.9g (44.75 grain) powder charge.

Naboj kal. 7,9mm wzor Przeciwpancerny Smugowy("PS") - {Cartridge, caliber 7.9mm, Armor Piercing Tracer Model}

This cartridge was very similar to the German S.m.K.Leuchtspur, differing only in that the hardened penetrator was shorter by about 1.5mm, while the cup containing the tracer element is similarly longer.  Closure of the base is made with a perforated washer and foil assembly, which covers the tracer igniter.  As with the P cartridge, the PS round was made to especially high standards for air force usage.  This is evidenced by box labeling with notations such as "do KM Lot.," "Lotn."  or "Lotnicze," all of which refer to air force use.  Boxes were printed with red lettering, and had a diagonal overprint, also in red, reading "Smuga Czerwona," which indicated a red trace composition.  PS cartridges were marked with a blue primer annulus and a painted bullet tip.  Early bullet tip marking was in blue, later in black.  A number of theories surround the difference in tip color.  One is that the black tipped bullets are for ground use.  Another was that the different colors indicated different trace and igniter compositions, with the blue tipped round being optimized for daytime use and the black for night.  A third is that the color difference indicated a higher level of quality control for rounds intended for air force use.  However, much of this is speculative, as a Polish document indicated that the black tipped variety would become standard once supplies of the blue tipped bullets ran out.

PS cartridges were packed fifteen to a box, and eighty-two boxes for a case, for a total of 1,230 rounds per case.  The PS round is normally found with a cupronickel clad steel jacket or a gilding metal clad steel jacket.  The bullet weighed 10g (154.3 grains), was 37mm (1.47") long, and had a 2.8g (44 grain) charge of either flake or tubular propellant.

Polish cartridge drawing, PS cartridge
Polish cartridge drawing, PS cartridge

Naboj kal. 7,9mm wzor Zapalajacy ("Z") - {Cartridge, caliber 7.9mm, Incendiary}
Polish incendiary cartridges came in two varieties, those intended for use in rifles and those intended for use in machine guns.  Cartridges with yellow tips and a yellow primer annulus were intended for rifles, while cartridges with all black bullets and a yellow primer annulus were intended for machine guns.  Both cartridges were packaged in boxes labeled with yellow ink.  The rifle incendiary bullet is similar to the German "Spitzgeschoss mit Phosphor" (pointed bullet with phosphorus) or S.Pr. type.  However, there is speculation that it was not the German cartridge to which the rifle Z round can trace its history, but rather the Belgian FN incendiary round.  The Belgian bullet is identical to the Polish bullet, and given the fact that FN supplied both weapons and technical assistance, the development of an incendiary bullet from Belgian sources is not unlikely.  The rifle bullet has the same profile as the S bullet.

The machine gun incendiary bullet is found with the profiles of both the S and SC bullets, and is clad with gilding metal, which, while a rarity in Polish 7.9mm ammunition, may have been added to promote the chemical blackening of the bullet.  The reason for the issuance of two incendiary rounds of the same caliber is largely unknown, but it is possible that the rifle incendiary round may have served double duty as a spotting or observation bullet.  The rifle incendiary bullet weighed 10.36g (159.8 grains), was 36.83mm (1.45") long, and had a 2.86g (44.13 grain) charge of propellant.  The machine gun incendiary bullet weighed 9.72g (149.9 grains), was 37.33mm (1.47") long, and had a 2.9g (44.75 grain) charge.

Naboj kal. 7,9mm slepy do Kbi, Kbk - {Cartridge, caliber 7.9mm, Blank for rifles, short rifles and carbines}
Naboj kal. 7,9mm slepy do K.m. - {Cartridge, caliber 7.9mm, Blank for machine guns}

These are early style blank cartridges that derive from the original Austro-Hungarian types with wooden bullets 31mm (1.22") in length.  It is believed that those blank cartridges with dark blue bullets were intended for rifles while those with dark brown or reddish bullets were destined for machine gun use.  Bullets were hollow and light weight.  The machine gun bullet was 1.45g (14.1 grains) and the rifle bullet 0.92 grains (10 grains).

Early Polish cartridges and blanks used the Austro-Hungarian form of primer ignition, which consisted of a central flash hole through the case anvil.  This Austrian influence was due to the state appropriation of Austrian plants located in the territory assigned to Poland after the 1918 armistice and the establishment of the Pocisk plant in Warsaw by Hirtenberger.  The Poles used once fired cases, cases unsuited for full power loading, and German World War One brass for blanks.  Polish blanks will have a light grey primer annulus.

Polish cartridge drawing, Blank cartridge
Polish cartridge drawing, blank cartridge
Naboj kal. 7,9mm slepy do Kbi, Kbk (nowego wzoru)- {Cartridge, caliber 7.9mm, Blank for rifles, short rifles and carbines, new model}
Naboj kal. 7,9mm slepy do r.k.m., c.k.m. - {Cartridge, caliber 7.9mm, Blank for light and heavy machine guns}
These "new model" blanks had a grey primer annulus and a reddish bullet if intended for machine guns and a blue bullet if intended for shoulder arms.  The bullets were 32mm long, and had thicker walls.  Box label printing was in grey ink.

Naboj kal. 7,9mm slepy do K.m. Hotchkissa wz25 - {Cartridge, caliber 7.9mm, Blank for Hotchkiss Model 25 machine gun}
This was a special blank produced for the Hotchkiss 14/25 machine gun and had a natural wood bullet with a conical point.  The bullet was 31mm long and weighed 0.43g (6.6 grains).

Naboj Szkolny - {Cartridge, dummy}
The initial type of official Polish dummy round was formed from one piece of hollow brass.  A second variant was made from a lathe turning of brass with a large knurled band at the base, and a primer pocket filled with a rubber composition.  Another version had copper in the base, and was produced with and without the knurled band.  There was also a chrome plated version with an SC bullet and four radially disposed holes.

7,9mm Luska naboju do strzelania izbowego - {7.9mm cartridge case for gallery shooting}

This cartridge was an auxiliary device for indoor short range training with standard service rifles.  The cartridge was obsoleted in about 1933 with the general issue of .22 rimfire training rifles.  The cartridge featured a brass case-like holder that chambered in the service rifle.  This holder had a provision for a snap on bullet or kulka, that weighed 2.8g (43.2 grains), and was 10.5mm (0.413") high.  The kulka was propelled by a special primer called a splonka, that looked like a miniature blank.  It was 5.74mm (0.225") in diameter, and 7.1mm (0.279") in length.  The primer compound was a mixture of smokeless and black powder.  After firing, the holder was ejected as a normal case, and decapped with a special tool.  The gallery cartridges were made by Pocisk.
Polish 7,9mm gallery cartridge
Polish cartridge drawing, gallery cartridge
Contrary to historical myth, the equipment with which Polish forces were supplied at the beginning of the war was not substandard, poorly made, or antiquated.  The Polish Air Force actually fielded some of the most advanced attack aircraft in the world, while her army could boast some of the most modern armor designed to that time.  Poland's real failure lay in adopting tactics and creating a force structure geared toward winning the First World War and Pilsudski's campaigns of the 1920's; that is to say an army designed to win the last war.  Such thinking on the part of military planners is not atypical, and surely neither Great Britain nor France could have boasted any better in 1939.  If Polish forces were equipped with weapon systems that were as good as, if not better than, those of their contemporaries, they were also equipped with small arms ammunition that was, in a word, superb.  Polish 7.92mm ammunition was in many ways better made, better designed, and more innovative than the German originals.   Indeed, in the 1930's Polish exports of 7.92mm ammunition were on the beginning of a precipitous rise.  One can only wonder how prevalent Polish arms and ammunition would have become in the absence of World War Two.

Note: Data for this month's trivia page was gathered from:

Kent, Daniel W., German 7,9mm Military Ammunition, 1888-1945, (Self Published: 1990)

German 7,9mm Military Ammunition, 1888-1945 is available from the John C. Denner Company.  Click on the image to order.
German 7,9mm Military Ammunition

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