8×63mm patron m/32 explained

8×63mm
Origin:Sweden
Type:Rifle
Service:1932–1975
Used By:Sweden
Wars:UN intervention in Kongo 1960-1964
Designer:Kungliga Armétygförvaltningen (KAF)
AktieBolaget Bofors
Design Date:1927–1932
Manufacturer:AB Bofors
Is Si Specs:yes
Case Type:Rebated, bottleneck
Bullet:8.20
Neck:9.10
Shoulder:11.51
Base:12.43
Rim Dia:12.18
Rim Thick:1.42
Case Length:62.81
Length:84.62
Primer:Berdan, Large rifle
Is Si Ballistics:yes
Bwunit:gram
Bw1:14.2
Btype1:m/32 FMJ
Vel1:760
En1:4101
Test Barrel Length:609 mm (24 in)
Balsrc:[1]

The 8×63mm patron m/32 was a bottlenecked centrefire cartridge with a slightly (0.25mm) rebated rim for Swedish heavy and medium machine guns. It was used from 1932 to the finalisation of the re-chambering process of these machine guns to 7.62×51mm NATO in 1975.

History

Given the experiences of the devastating effect of small arms fire, including the long-range, even indirect fire of the machine guns, in the Russo-Japanese War and World War I, as well as a revolution in terminal ballistic calculations, calibre-related concerns occupied a lot of attention worldwide in military establishments. Sweden was no exception, and series of trials in calibres 6mm-12mm were conducted until the late 1920s. At this time, the standard service cartridge in Swedish use was the 6.5×55mm Swedish skarp patron m/94 projektil m/94 (live cartridge m/94 projectile m/94) service ammunition loaded with a 10.1g long round-nosed m/94 (B-projectile) bullet. After study-travels by Lieutenant Colonel de Laval along with Captains Nygren and Holmgren, mainly to Germany and the Netherlands in October 1930, Royal Swedish Army Materiel Administration (Kungliga Armétygförvaltningen (KAF) appointed a commission that conducted a series of tests with calibres 6,5 mm to 7,2 – 7,5 – 7,9 mm, and bullet weights between 8.4 grams and 17.0 grams, with the intention to either recommend a new calibre for the kulspruta m14-29 or retain the 6.5×55mm but with a new boat tailed spitzer bullet, as the old blunt nosed projectile m/94 had inferior ballistics.The commission found that at ranges below 24000NaN0, no recommendation could be given without indepth analysis of intended tasks within the tactical doctrine. Past this, the 14.2 gram bullet in calibre 7.9mm had superior performance in precision and penetration while not causing excessive barrel wear as well as fulfilling the requirement of 20 kilogram-metres impact force up to a range of 36000NaN0. Based on this, KAF tasked AB Bofors to develop and manufacture the larger rifle cartridge to meet these needs.

Design

The patron m/32 round had the same overall length as the .30-06 Springfield cartridge, which allowed it to fit in the standard Browning receiver, but used a larger diameter case and share the 6.5×55mm 12.2mm diameter bolt face. Compared to the 1928 pattern .30-06 Springfield M1 Ball the 8×63mm patron m/32 was loaded with 8.2mm S bore 14.21NaN1 bullets and had more muzzle energy. The 8×63mm patron m/32 had a muzzle velocity of 7600NaN0 and an operating pressure of 3300NaN0.

The patron m/32's aerodynamically refined boat tailed spitzer bullet had a useful range of approximately 36000NaN0 on which the impact energy was 20 kilogram-meters (196 J / 145 ft⋅lbf),[2] [3] and a maximum range of approximately 55000NaN0 when fired from a kulspruta m/36.[4] Reverse engineering the trajectory from the previous sentence indicates a ballistic coefficient (G1 BC) of approximately 0.63.Available with armour piercing bullets, patron m/32 was used in the UN-forces' KP-bil during the Congo-crisis against the separatists' armoured cars.

The 8×63mm patron m/32 cartridge was used in the following machine guns:[5]

The 8×63mm patron m/32 was also used in the gevär / pansarvärnsgevär m/40[6] bolt-action rifle, Karabiner 98k's re-chambered in Sweden for the patron m/32. Originally purchased as the pvg m/39 in 8×57 IS as a stop-gap anti-tank rifle (despite being unsuited for the role), the re-chambered 8×63 rifles were designated m/40, and later issued to machine gun crews so their rifles would fire the same round as their machine guns. Besides the rechambering a muzzle brake was added necessitated by the additional recoil produced by the more powerful 8×63mm patron m/32 cartridge.

Military ammunition

DesignationTypeWeights (gram)Propellant typeProjectile material(s)Muzzle velocity V0 or V25Burning rangeMarkingRemarks
CartridgeProjectilePropellant
8 mm sk ptr m/32FMJ32.1abbr=onNaNabbr=on14.13abbr=onNaNabbr=on3.6abbr=onNaNabbr=onKspkr 1/0,55Lead core, Nickel jacket750 m/s (V25)NoneStandard Ball.
8 mm sk ptr m/32"For peacetime only"FMJ32,1714,23,6Kspkr 1/0,55Lead core, Nickel jacket760m/sBlue tipAmmunition of inferior quality.Used in peacetime.
8 mm sk ptr m/32"Not for machine guns"FMJ32,1714,23,6Kspkr 1/0,55Lead core, Nickel jacket760 m/sGreen tipSame as above but has green marking.This means "Not for machine guns"
8 mm sk ptr m/32 pprj m/39AP29,711,83,6Kspkr 1/0,55 pbr3,2 g steel core780-810 m/sBlack tipOrdinary armor-piercing cartridge. Penetration of ~10 mm at 50 m
8 mm sk ptr m/32 pprj m/40or 8 mm pbr ptr m/32-40AP31,1415,73,6Kspkr 1/0,55 pbrTungsten core725 m/sTop half blackTungsten-cored ammunition. Penetration of ~20 mm at 0 mOnly used in machine guns.
8 mm sk ptr m/32 slprj m/39Tracer28,911,013,6Kspkr 1/0,55Projectile contains phosphorus, no boat tail780-824 m/sred 100-800 mRed tipFirst marking of slprj m/39
White tipSecond marking of slprj m/39.
8 mm sk ptr m/32 slprj m/39

"with a different primer"

Tracer28,911,013,6Kspkr 1/0,55Projectile contains phosphorus, no boat tail780-824 m/sRed 100-800 mRed tipThe primer is dark gray and non-magnetic. Likely manufactured in Germany.
8 mm sk ptr m/32 brandprj m/40Incendiary11,55Phosphorus and leadYellow tipIncendiary ammunition from Hungary. Trubbkula.
8 mm sk ptr m/32 brandprj m/41Incendiary/AP27,79,8-9.93,6Kspkr 1/0,55 pbrHas an internal steel core surrounderd by fuel835-930 m/sOrange tipThe ammunition is primarily for aircraft and is a semi-armor piercing projectile
8 mm Tysk B patron"Observation cartridge"High-explosive incendiaryBottom halve blackGerman B bullet loaded in a Swedish 8×63 cartridge.
8 mm sk blindptr m/32DummyNoneEarly marking.
8 mm sk blindptr m/32DummyGreen tipLate marking.

The operating pressures of the various ammunition types varied between 330-.

See also

External links

Notes and References

  1. http://weaponland.ru/board/patron_8x63_swedish_8x63_bofors/44-1-0-409 8x63 Swedish / 8x63 Bofors (in Russian)
  2. The useful maximum 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).
  3. Kjellgren, G. L. M. . The Practical Range of Small Arms. https://web.archive.org/web/20150305142959/http://www.krtraining.com/KRTraining/Archive/PracticalRangeSmallArms.pdf . 5 March 2015 . The American Rifleman . 40–44. live.
  4. http://www.forgottenweapons.com/swedish-kulspruta-m36/ Swedish Kulspruta m/36 at forgottenweapons.com
  5. http://gotavapen.se/gota/artiklar/rifles_se/gev40/gev40_1.jpg Arméplanch för utbildning fotograferad av Göta Vapenhistoriska Sällskap (in Swedish)
  6. http://www.evhf.se/EVHF/Texter_files/Fra%CC%8Agor%20samt%20fo%CC%88rso%CC%88k%20till%20svar.pdf Sammanfattning av rapport Till Kungl. Arméförvaltningens artilleridepartement (in Swedish)