How much ofdifference in recoil is there between the two? I realize that a lot of factors can mitigate recoil but assume both are in factory non-light-moutain type appropriate rifles.

Thanks..

Here is a recoil calculator. http://www.handloads.com/calc/recoil.asp

Shooting 250 grain partitions from a 338 factory ammo vs 270 grain 375 I think the 375 is not as harsh. Bear in mind that a 338 are a lighter rifle then most 375's out there with the exception of Remington and a few others.