The spitzer bullet (or spire point) is a pointed projectile that is primarily used in small-arms. The pointed nose shape, which was developed for military purposes in the late 19th and early 20th century, was a major design improvement compared to earlier rounder or flatter-tipped bullets because pointed nose shapes were less susceptible to external ballistic factors like drag. By adding a point, projectiles made for fully-powered and intermediate rifle cartridges obtain a lower drag coefficient, which makes them decelerate less rapidly. Lowering the drag coefficient leads to improved external ballistic behaviour.[1]
The development of spitzer bullets and long-range volley sights for service rifles changed military doctrines. Area targets at ranges up to 1420– could be subject to rifle fire. With improvements in machine guns at the turn of the 20th century, the addition of clinometers meant that fixed machine gun squads could deliver plunging fire or indirect fire at more than 3000abbr=onNaNabbr=on. The indirect firing method exploits the maximal effective range, that is defined by the maximum range of a small-arms projectile while still maintaining the minimum kinetic energy required to put unprotected personnel out of action, which is generally believed to be 15 kilogram-meters (147 J / 108 ft⋅lbf).[2]
Spitzer bullets greatly increased the lethality of the battlefields of World War I. Before, during and after World War I, militaries adopted even more aerodynamically refined spitzer projectiles by combining a pointed nose with a slightly tapered base at the rear, called a boat tail, which further reduced drag in flight.[3] These projectiles were known as spitzer boat-tail bullets which increased the terminal maximum ranges of fully-powered rifle cartridges to between 4115and.
The name "spitzer" is an anglicized form of the German word Spitzgeschoss, literally meaning "pointed projectile".
From the mid to late 19th century, European military research had started to examine how to maximise available small arms muzzle velocity through improved projectile design. Stronger metal casings were being used to contain cartridge propellants, making small arms more powerful but not any more accurate. Designers knew that bullets with a lower drag coefficient (Cd) would decelerate less rapidly and therefore travel further. A lower drag coefficient also flattens the projectile's trajectory, making it more stable in flight and less susceptible to lateral drift caused by crosswinds. By retaining a higher impact velocity, bullets with high ballistic coefficients would retain more kinetic energy and be lethal at greater ranges. It was these requirements that drove military thinking in the years prior to the First World War.
The spitzer bullet design was first introduced in 1898 as the Balle D by the French Army. The Balle D bullet was designed by Captain Georges Raymond Desaleux, in order to improve the ballistic performance of the existing French 8×50mmR Lebel service cartridge of 1886.
The original 1886 pattern 8×50mmR Lebel cartridge was an innovative service cartridge design, since it was the first military cartridge to use single-base smokeless, nitrocellulose based, (Poudre B) gunpowder as developed by Paul Vieille in 1884. The original 1886 pattern 8×50mmR Lebel was loaded with a 15g cupro-nickel-jacketed lead-cored flat-nosed wadcutter-style Balle M bullet designed by lieutenant colonel Nicolas Lebel achieving a muzzle velocity of 628m/s.
The new 1898 pattern 8×50mmR Lebel cartridge loaded with Desaleux's new lighter 12.8g Balle D brass mono-metal spitzer bullet achieved a muzzle velocity of 700m/s, providing a somewhat flatter trajectory and a greatly improved maximum effective range. Besides having a pointed nose section the Balle D was also the first military rifle projectile that had a boat tail – a streamlined tapered base – to further minimize air resistance in flight.[4]
The 1898 pattern 8×50mmR Lebel Balle D spitzer nose profile combined with the boat tail resulted in a ballistic coefficient (G1 BC) of 0.568 to 0.581 (ballistic coefficients are somewhat debatable). Fired at 700m/s muzzle velocity the Balle D bullet retained supersonic velocity up to and past 800m (2,600feet) (V800 ≈ Mach 1.13) under ICAO Standard Atmosphere conditions at sea level (air density ρ = 1.225 kg/m3) and had a maximum terminal range of approximately 44000NaN0. Even by 21st century standards 800m (2,600feet) typical effective supersonic range is regarded as normal for a standard military rifle round.[5]
| Distance (m) | 0 | 200 | 400 | 600 | 800 | 1000 | 1500 | 2000 | |
|---|---|---|---|---|---|---|---|---|---|
| Trajectory (m) | 0 | 0.14 | 0.81 | 2.39 | 5.27 | 9.83 | 31.71 | 75.61 | |
| Velocity (m/s) | 628 | 488 | 397 | 335 | 290 | 255 | 197 | 160 |
| Distance (m) | 0 | 200 | 400 | 600 | 800 | 1000 | 1500 | 2000 | |
|---|---|---|---|---|---|---|---|---|---|
| Trajectory (m) | 0 | 0.12 | 0.54 | 1.43 | 3.01 | 5.60 | 18.30 | 44.0 | |
| Velocity (m/s) | 700 | 607 | 521 | 448 | 388 | 342 | 278 | 240 |
The downrange performance tables above show the superior velocity retention of the Balle D compared with its Balle M predecessor
Note: The air density ρ used to correlate these tables is unknown.
In 1932, 8×50mmR Lebel Balle N ammunition was introduced, which featured a lead-cored, cupro-nickel-over-steel-jacketed, pointed boat-tail bullet weighing 15.0 g (232 grains). It had been designed to improve the long-range performance of the issued Hotchkiss Mle 1914 machine guns.
In Germany the Gewehr-Prüfungskommission (G.P.K.) (Rifle Testing Commission) was responsible for improving the accuracy and performance of the 1888 pattern military M/88 ammunition and Germany's weapons chambered for M/88 ammunition like the Gewehr 1888. During a late 19th and early 20th century improvement program tasked with remedying the M/88's propellant compression and excessive barrel (grooves) wear problems, the German ordnance authority began to prefer spitzer bullets by 1898.
A new Spitzgeschoß aerodynamic bullet, credited to the independent ballistician Arthur Gleinich, was tested in 1902 and officially adopted on 3 April 1903. After several shape revisions it entered mass production in 1904. The Spitzgeschoß nose was externally pointed like the French design and its shape was patented, but the full metal jacket Spitzgeschoß differed internally.[6] [7] [8] The Gewehr-Prüfungskommission program resulted in the S Patrone or 7.92×57mm Mauser cartridge, which was loaded with a relatively lightweight 9.9g spitzer bullet with a slightly increased diameter of 8.2abbr=onNaNabbr=on that had a ballistic coefficient (G1 BC) of approximately 0.321 to 0.337 (ballistic coefficients are somewhat debatable), along with a dimensionally redesigned chambering and bore (designated as "S-bore") and new double-base (based on nitrocellulose and nitroglycerin) smokeless powder loading, which delivered a greatly improved muzzle velocity of 878m/s from a 740mm barrel. The S Patrone was adopted by the German Army and Navy in 1903 and had a maximum terminal range of approximately 3700-1NaN-1.[9] [10] The combination of increased muzzle velocity and improved bullet aerodynamics provided a much flatter bullet trajectory, which increased the probability of hitting an individual target at most typical combat distances.
At the onset of World War I, Germany developed an aerodynamically further refined bullet. This 12.8g full metal jacket s.S. (schweres Spitzgeschoß, "heavy spitzer") boat tail projectile had a ballistic coefficient (G1 BC) of 0.557 to 0.593 (ballistic coefficients are somewhat debatable) and was loaded in the s.S. Patrone. At 7600NaN0 muzzle velocity the s.S. Patrone had a maximum terminal range of approximately 4700-1NaN-1 and retained supersonic velocity up to and past 1000m (3,000feet) (V1000 ≈ Mach 1.07) under ICAO Standard Atmosphere conditions at sea level (air density ρ = 1.225 kg/m3). From its 1914 introduction the s.S. Patrone was mainly issued for aerial combat and as of 1918 in the later stages of World War I to infantry machine gunners. Fifteen years after World War I the S Patrone was phased out and the s.S. Patrone became the standard issue ball ammunition for the German military.[11] [12]
In 1906, United States ordnance authorities arranged to purchase the production license for the Spitzgeschoß bullet design from Gleinich. Now referred to as a 'spitzer' design, the new 9.7g flat base projectile that had a ballistic coefficient (G1 BC) of approximately 0.405 with a cupro-nickel alloy jacket was incorporated into the M1906 .30-06 Springfield cartridge adopted by U.S. armed forces in 1906. The Ball, M1906 rounds had a muzzle velocity of 8230NaN0 and had a maximum terminal range of approximately 31170NaN0 and can be identified by their silver-colored bullets. The cupro-nickel alloy was found to foul the bore quickly.
In 1908, the Russian Empire adopted a new 7.62×54mmR service round variant loaded with the "L" 9.61g Лёгкая Пуля (Lyogkhaya pulya, "Light Bullet") spitzer bullet that had a ballistic coefficient (G1 BC) of approximately 0.338. The 7.62×54mmR M1908 Type L cartridge had a muzzle velocity of 8650NaN0.
In 1910, the United Kingdom of Great Britain and Ireland officially adopted the .303 British Mark VII cartridge variant loaded with an 11.3g flat base spitzer bullet that had a ballistic coefficient (G1 BC) of approximately 0.467. The .303 British Mark VII cartridge had a muzzle velocity of 7440NaN0 and a maximum terminal range of approximately 2743m (8,999feet).[13] [14]
In 1911, Switzerland adopted the 7.5×55mm GP 11 cartridge loaded with a 11.3g spitzer full metal jacket bullet. Besides a pointed nose, the GP 11 bullet also had a boat tail to further lower the drag coefficient (Cd). The GP 11 projectile had a ballistic coefficient (G1 BC) of 0.505 to 0.514 (ballistic coefficients are somewhat debatable) and had a maximum terminal range of approximately 55000NaN0 under Swiss chosen atmospheric conditions (altitude = 8000NaN0, air pressure = 6492NaN2 Hg, temperature = 7°C) equaling ICAO Standard Atmosphere conditions at 653.20NaN0 (air density ρ = 1.150 kg/m3). At 7800NaN0 muzzle velocity the standard GP 11 ball spitzer bullet retained supersonic velocity up to 800m (2,600feet) (V800 ≈ Mach 1.1) under ICAO Standard Atmosphere conditions at sea level (air density ρ = 1.225 kg/m3). The GP 11 bullet set off the militaries of countries like Germany, the United States and the United Kingdom at the onset of and after World War I to develop and field similar full metal jacket boat tail spitzer bullets to improve the maximum effective range and long range performance of the full metal jacket flat based spitzer bullet designs they used. The useful maximum effective range is defined by the maximum range of a small-arms projectile while still maintaining the minimum kinetic energy required to put unprotected personnel out of action, which is generally believed to be 15 kilogram-meters (147 J / 108 ft⋅lbf).[15]
In 1913, the ordnance authorities of the Kingdom of Spain issued a redesigned 7×57mm Mauser cartridge (7mm Cartucho para Mauser Tipo S).[16] It was loaded with a 9g spitzer bullet fired at a muzzle velocity of 8500NaN0 with 3251abbr=onNaNabbr=on muzzle energy from a 5891NaN1 long barrel. It had a maximum terminal range of 3700-1NaN-1.[17]
In 1932, Sweden introduced the 8×63mm patron m/32 loaded with 14.2g spitzer bullets with a boat tail fired at a muzzle velocity of 7600NaN0 bullets. The 8×63mm patron m/32 ammunition was not developed as general service ammunition but for anti-aircraft and indirect fire and had an effective range of approximately 36000NaN0 on which the impact energy was 20 kilogram-meters (196 J / 145 ft⋅lbf), and a maximum terminal range of approximately 55000NaN0 when fired from a Kulspruta m/36 machine gun.[18]
Sweden and Norway loaded their 6.5×55mm m/94 service ammunition with a 10.1g long round-nosed bullet (B-projectile) fired at a muzzle velocity of 7250NaN0 up to the early phase of World War II and Norwegian occupation by German in 1940. From 1941 onwards Sweden, which remained neutral during World War II, adopted m/41 service ammunition loaded with a 9.1g spitzer bullet (D-projectile) fired at a muzzle velocity of 8000NaN0.[19] Besides a pointed nose the m/41 D-projectile also had a boat tail.[20]