[elkhunter11]

So shooting the same load in two rifles with different twist rates produced a difference in velocity of only 10fps? Has anyone actually measured the pressure produced in both barrels with the same load? If the fast twist barrel is producing more pressure , then you would need to change the load to produce equal pressure in both barrels to determine the true effect of twist rate on velocity. And even if the same pressure only produces 20fps more with a slow twist barrel, why not take advantage of that 20fps if the accuracy is the same? If I am only going to shoot a 55gr bullet , why use a twist that is optimum for 80gr, and give up 20fps that I can have for nothing?
I have owned six 7mmstw rifles, four with a 1 in 10" twist, and two with a 1 in 9" twist. All shot 140-150gr bullets well, but the 1 in 9" rifles did not shoot the 140gr bullets as well as they shot 150 gr bullets. The 1 in 10" rifles preferred the 140gr bullets. So is this simply coincidence, or is the twist rate a factor? And this is with only a 1" difference in the rate of twist.