The 300 Blackout pistol cartridge is very efficient, providing up to 14% more energy in a same length barrel as the 7.62x39 round! Plus it is the quietest 30 cal round available using subsonic ammo and a suppressor. Most of the subsonic rounds are match grade heavy bullets that dont slow down. It retains nearly as much energy at 300 yards as it does at the muzzle! This is the best choice for a pistol for sound and retained energy.