Firearm Ammunition & Cartridges

7.5 FK Ammunition

7.5 FK calibre ammunition is a proprietary calibre designed and produced by FK BRNO Engineering s.r.o. This caliber was designed specifically to bridge the gap between standard handgun and carbine rifle calibers in terms of power, efficiency, range, and accuracy. While at the same time it’s compact enough to be used in a standard size automatic pistol with a 5-inch or 6-inch barrel, and when used in pistols with FK BRNO’s patented recoil attenuating system, it has recoil comparable with calibers with less than half the kinetic energy. The following are calculations of conventional ballistic data for the 7.5 FK cartridge.

7.5 FK Ammunition

FK BRNO has developed and patented the DSI ,an alternative computational system for measuring the efficacy of handgun cartridges. This methods measures the probability of instant incapacitation when compared to other calibres. The development was based extensive field testing and recent and historic war casualty data. It is calculated as follows:

Dynamic Shock Index [DSI] = Meplat Diameter x impact velocity – (1500-impact velocity) x sectional density

The following are examples of how some powerful versions of popular ammunition calibres score using muzzle velocity for illustrative purposes (as opposed to impact velocity) in comparison with the 7.5 FK:

7.5 FK F9 FKB 0.236 1920 0.160 72.5
44 MAG 240 gr JHP XT 0.255 1280 0.185 50
7.5 FK F5/S95 FKB 0.157 2000 0.150 47.1
357 Mag 125gr JHP MT 0.248 1378 0.140 43.6
10 MM 180gr JHP BB 0.236 1250 0.160 37.8
45ACP 185gr +P JHP MT 0.255 1148 0.139 30.6
9 MM 124gr +P JHP GD 0.208 1262 0.140 29.8
9 MM 135gr +P JHP CD 0.157 1241 0.153 18.8