Police departments were switching to short barreled sniper rifles back in the 80s and the Federal Match 168-grain BTHP load was developed to meet the need for ammo to give efficient performance in 20 inch tubes. The 308 is capable of giving velocities of 2800 fps or more with loads developed for barrels of 22 inches or more. That's a greater than 32 fps difference from the 2670 fps from a 20 inch barrel reported in the article