And another factor for the recoil calculations (don't know if it makes any significant perceivable difference) is the "escape" velocity of the powder (gases) as it leaves the muzzle past the projectile. A portion of the gas exceeds the velocity of the projectile as soon as it leaves the muzzle (ie the gas is no longer contained or restrained and only has air resistance to battle) - this is a jet effect. Very hard to quantify but would add to the calculated recoil.

I've heard and read that in some of the larger capacity magnums, a faster powder will result in less perceived recoil than a slower one for the same projectile muzzle velocity but I guess the biggest component of this would be the fact there is usually less of the faster powder used.

I think I'm not all that recoil sensitive - I can't detect any difference between light or heavy projectiles in say 30/06 power range cartridges, or even in my 375H&H for that matter (220gn to 350gn). I do however notice the difference between a 400gn and 500gn in my 458WM.

But as it's been stated above, perceived recoil doesn't always line up with calculated recoil eg my friends Brno 602 in 300WM was more unpleasant to fire off a bench than my identical Brno 602 in 375HHMag, even though his rifle was very slightly heavier (they shared the same external barrel diameter) and produced less recoil on paper.