Since maximum pressure in rifle bores occurs when the bullet is already 4"-5" up the bore enroute to the muzzle, I see little problem with variation is seating depth of the bullets.......Take a look at charts showing the comparison of chamber pressures and bullet travel.

This phenomenon is what accounts for people being able to fire significantly oversize bullets safely if the case neck can expand sufficiently to freely release the bullet. An example is firing Mauser7,92mm S bullets in 7,8mm J-bored barrels after the chamber neck portionswere bored larger. (OR, firing .308" bullets in a 6.5mmArisaka that was rechambered onlyfor .30/'06 with no change in the bore of the rifle!)