Compact Battle Rifle - Suppressed/Subsonic - .338 Whisper - USA - 700 RPM - While subsonic loadings for pistol/SMG cartridges are fairly common, loading a rifle cartridge to subsonic velocities is typically an exercise in futility.  The cases are typically too large allowing the powder charge to move around leading to inconsistent ignition, velocities, and accuracy.  If these problem can be licked, there generally isn't enough gas pressure to function a gas-operated repeater.  

J.D. Jones, the intrepid owner of SSK Industries, took a different approach for his Whisper series.  He decided to use shorter cartridge cases that still fit the breechfaces of common automatic weapons.  For the .338 Whisper, the parent case is the 7mm Remington Benchrest, which shares the same case head diameter as the 7.62x51mm NATO.  The reduction in case length allows the use of long ogive bullets like the .338" 300gr Sierra MatchKing for the subsonic loadings.  With the high ballistic coefficient, the projectile loses very little of its already low velocity.  It also results in rather nasty terminal effects as the long projectile is prone to tumble upon impact with flesh.  

However, that's not all: The cartridge fits and feeds from standard 7.62x51mm NATO magazines with only minor modification, and J.D. can provide upper receiver units that will fit onto AR10/SR25 lower receivers.  These will even function in full-automatic fire with or without a suppressor attached.  Thus the user can switch back and forth between his SR25K upper receiver and the SSK .338 Whisper upper receiver depending upon the mission requirements.  D.E. Watters
