Just like I said... difference between 20"and 24" is right at 150fps (or the 20-40fps per inch I stated earlier).
Also... if you look at the 89fps jump from 20"-22" on the 7 Rem... it is out of whack with all the other increases... even in other calibers. All the other data (if you throw out the 89fps 7mm anomoly) shows an average of 42 fps per 2" of barrel. The loss is not nearly what most folks suspected, and the 7mm with a 20" pipe should still out perform the .280 Rem (or a .270 Winny) in a 24" snout... though the muzzle blast will be pronounced to say the least.
