The Cartridge

The 7.5 FK is a completely new proprietary cartridge caliber. The case is 27 mm long with a total length of 35 mm, and a head diameter of 10.8 mm. This caliber is not a necked-down version of any other caliber. The case is designed to withstand higher pressures than usually used in pistol calibers. 

Current Status / Use

The 7.5 FK is C.I.P (Permanent International Commission) registered and approved. It is a proprietary cartridge caliber, with intellectual property rights claimed and registered by FK BRNO. 

The main use of the caliber is for personal security detail (PSD), urban / suburban combat, backup short barrel rifle (SBR), Aircrew survival weapon, mechanised armour crew weapon, among others. 

It comes in three types of bullets: Spoon Tip; Hollow-Point Banded Frangible Nose; Hollow-Point Frangible Nose. All are monolithic and made from copper and copper alloys. 

Cartridge Specifications

Muzzle Velocity

610 m/s  (2000 fps)

Velocity at 100 Meters

465 m/s  (1525 fps)

Muzzle Energy

1200 J  (880 ft/lbs)

Energy at 100 Meters

700 J  (520 ft/lbs)

United States Bullet Weight

6.17g (95 gr) Hollow Point All Copper

European Bullet Weight(s)

6.67g (103 gr) Spoon Tip Cu Alloy

6.17g (95 gr) Hollow Point All Copper

7.5 FK

Development / History


Although the basic case design and the concept of the cartridge was finalized in 2011, more than 250,000 rounds were fired with at least 15 different case design variations and over 30 different bullet designs were tested over a four-year period before the final cartridge design form was approved for production. 


    The 7.5 FK was initially developed to fulfill a requirement for a new cartridge, by a private customer in 2010. That requirement was addressing the shortfall of hand held and shorter/smaller firearms that were used in their relevant theater of action and bridged the gap between standard/popular pistol caliber and rifle calibers.This requirement was subsequently canceled however the initial tests showed a very high accuracy potential which prompted the developers to continue with the cartridge as a target and long range pistol competition round, in addition to the original intended use. 

      Main Design Parameters

      Cartridge must be short and small enough to be used comfortably in magazine fed / in grip magazine, size of firearm.

      Ballistics must be designed for a max barrel length of 150 mm, and projectile must be supersonic at 150 meters.

      Recoil force should not exceed power factor 230, [ .45 ACP +P ]

      Accuracy/ precision at 100 meters must be less than 100x100 mm rectangle.

      Projectile must create hydrodynamic shock at impact range of 100 meter (110 yard) in targets with a weight of up to 150Kg (330 lbs).

      Projectile permanent wound cavity in ballistic gel at 150 meters must be minimum 35 mm diameter and 300 mm in length.