Warning! Notes: The 300 Whisper is a new concept in the development of small-case-capacity, highly efficient cartridges combined with bullets of extreme ballistic efficiency. This is a special-purpose design by J.D. Jones of SSK Industries based on a 221 Remington case necked up to 308 caliber. It is intended to fire extremely heavy, accurate, ballistically efficient bullets at subsonic velocities in suppressed guns. It delivers more energy more accurately than any other subsonic round at 200 yards. In addition, it has interesting supersonic capabilities above 1,160 fps, thus offering greater versatility than any other cartridge capable of performing in these vastly differing arenas. Because powder charges are very small, suppressor size is proportionately smaller. (Cartridges of the World 9th Edition)
Be Alert: Publisher cannot be responsible for errors in published load data.