I failed to post this when I first added to my site last Christmas (Christmas present to me). Comparative ELR Cartridge Matrix (http://www.elr-resources.com/ELR%20Cartridges%20Matrix%2012252013.xls) - an Excel spreadsheet comparing three groups of cartridges - 338, 375, and greater than 375 caliber (tabs at the bottom of the spreadsheet). Beyond just "stat" data it includes JBM trajectory data as to when these various cartridges theoretically go subsonic. I used "published" velocity data (noting the sources). Some velocities may be over/under "reality". I also tried to use the same "type" projectile for the 338 and 375 - SMKs (using JBM's "Litz" data for the 338). Using SMK data sub-optimizes the subsonic distance but allows for a more "normalized" comparison. Using higher BC projectiles can extend subsonic by several hundred yards - just plug the alternate projectile into theJBM calculator (JBM link). With the recent announcement of the Unlimited Range ShootersAssociation (URSA), I find this info particularly interesting - the highest levels of recognition will require some very stout hardware and loads and many shooters will be going subsonic to connect.