7.62x53mmR

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7.62x53mmR
Type Rifle
Place of origin Flag of Finland Finland
Service history
In service 1891 to present
Used by Finland
Production history
Designed 1918
Produced 1918 to present
Specifications
Parent case 7.62x54mmR
Case type Rimmed, necked
Bullet diameter 7.83 mm (0.308 in)
Neck diameter 8.55 mm (0.337 in)
Shoulder diameter 11.61 mm (0.457 in)
Base diameter 12.42 mm (0.489 in)
Rim diameter 14.40 mm (0.567 in)
Rim thickness 1.60 mm (0.063 in)
Case length 53.50 mm (2.106 in)
Overall length 77.00 mm (3.031 in)
Case capacity 4.16 cm³ (64 gr H2O)
Rifling twist 300 mm (1 in 11.81 in)
Primer type Berdan
Maximum pressure 390 MPa (57,000 psi)
Ballistic performance
Bullet weight/type Velocity Energy
185.4 gr (12.01 g) FMJ 812 m/s (2,660 ft/s) 3,960 J (2,920 ft·lbf)

The 7.62x53mmR (aka 7.62x53mmR Finnish) rifle cartridge is a Finnish design based on the Russian 7.62x54mmR round dating back to 1891.

After gaining its independence in 1917 and after the Finnish Civil War of 1918, large numbers of Model 1891 Mosin-Nagant rifles were in the hands of the Finnish military. As the old barrels were worn out, they were replaced by new 7.83 mm (.308 in) barrels and the leftover 7.62x54mmR cartridges being in short supply, a domestic product was needed. This gave birth to the 7.62x53mmR.

Contents

[edit] Overview

The 7.62x53mmR is practically interchangeable with the 7.62x54mmR, the 54R will fit into the smallest allowed chamber size for the 53R, but is nevertheless a different cartridge made to different C.I.P. standards. Using military steel-jacketed 54R Russian ammunition in weapons made for 53R Finnish is not recommended, as it may rapidly wear out the barrel. Even worse, there is a possibility that the resulting pressure from the steel-jacketed larger diameter bullet is too much and firing it may result in severe damage to both the rifle and the shooter. Using the 53R Finnish in a rifle made for the 54R Russian is however safe, although it may result in accuracy well below the weapon's potential.

The cartridge remains in military use to this day, although it is now only used by the 7.62 mm TaK 85 sniper rifle. PKM machine guns and other Russian weapons in Finnish use are using the 7.62x54mmR exclusively.

[edit] Cartridge dimensions

The 7.62x53mmR has 4.16 ml (64 grains) H2O cartridge case capacity. The exterior shape of the case was designed to promote reliable case feeding and extraction in bolt action rifles and machine guns alike, under extreme conditions.

7.62x53mmR maximum C.I.P. cartridge dimensions.All sizes in millimeters (mm).

Americans would define the shoulder angle at alpha/2 ≈ 18.5 degrees. The common rifling twist rate for this cartridge is 300 mm (1 in 11.81 in), 4 grooves, Ø lands = 7.59 mm, Ø grooves = 7.83 mm, land width = 4.20 mm and the primer type is Berdan or very rarely large rifle.

According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) guidelines the 7.62 x 53 R case can handle up to 390 MPa (56,564 psi) piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers.

[edit] Differences between 7.62x53mmR (Finland) and 7.62x54mmR (Russia)

  • Round length: 77.00 mm (54R: 77.16)
  • Case length: 53.50 mm (54R: 53.72)
  • Rim diameter: 14.40 mm (54R: 14.48)
  • Bullet diameter: 7.83 mm (54R: 7.92)

[edit] Nominal charge

  • Muzzle energy: 3,960 J

[edit] See also

[edit] References

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[edit] External links

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