https://rifleshooter.com/2015/04/7mm-remington-magnum-7-rem-mag-barrel-length-versus-velocity/Here's an article on a 7mm Rem Mag test with velocity loss documenting per inch. Different cartridge, but I think you'll see slightly less loss due to smaller case capacity of your cartridges. His average loss with the 7mm Rem Mag per inch was 26fps.
