One thing I forgot to mention in my above post from yesterday:
I always lube my cases before resizing them, even if I'm using carbide dies. The brass moves through the die much more smoothly than when dry and requires little force to push it in and/or withdraw it. Dry brass often takes a LOT of energy to withdraw from a die, carbide die or not. Consequently, with lubed cases, there should be no excessive force on the brass that would cause any possible stretching. This might be an added reason why my fired brass doesn't require additional trimming after it has been fired more than once.
Again, this is only an observation so don't take it as the rule.