6.45×48mm XPL Swiss

6.45x48mm XPL Swiss (or 6.45x48 GP 80) is an experimental intermediate rifle cartridge that was developed in conjunction with the SIG SG 550 rifle as a potential successor to the 7.5×55mm Schmidt–Rubin cartridge.[1] The rimless cartridge has a base diameter of 11.82 mm (similar to the 7.62×51mm NATO) and a case length of 47.72 mm.[2] The bullet is an unusual 6.65 mm diameter (6.45mm refers to the bore diameter), fractionally smaller than the common 6.5 mm (bore diameter) bullet. The 97 gr (6.3 g) bullet was fired at a muzzle velocity of 900 m/s (3,000 ft/s) with 2,550 J (1,880 ft⋅lb) of muzzle energy.

6.45x48mm XPL Swiss
Type	Rifle
Place of origin	Switzerland
Production history
Designer	Swiss Army
Designed	1979-1980
Specifications
Parent case	7.62×51mm NATO
Bullet diameter	6.65 mm (0.262 in)
Neck diameter	7.56 mm (0.298 in)
Shoulder diameter	10.95 mm (0.431 in)
Base diameter	11.82 mm (0.465 in)
Rim diameter	11.81 mm (0.465 in)
Rim thickness	1.55 mm (0.061 in)
Case length	47.72 mm (1.879 in)
Overall length	65.06 mm (2.561 in)
Ballistic performance
Bullet mass/type Velocity Energy 6.3 g (97 gr) 900 m/s (3,000 ft/s) 2,550 J (1,880 ft⋅lbf)
Source(s): http://www.quarryhs.co.uk/Assault.htm

The cartridge was not adopted, the SIG SG-550 went into production with the 5.6×45mm GP 90 round.

Weapons using the 6.45mm cartridge

• 
  The C42 by Waffenfabrik Bern (Rifle version)
• 
  The C42 by Waffenfabrik Bern (Carbine version)
• 
  The SIG 541 (Carbine version)

References

1. http://www.quarryhs.co.uk/Assault.htm
2. http://www.municion.org/Swiss/645x48Xpl.htm