Over the years, I've killed a bunch of elk with both a 270 using 150 gr bullets and a 300 WSM with 180's. I never had a hit one get away with either caliber but I choose my shots. I don't just throw lead. I will say, though, that I feel like the ones hit with the 300 go down faster on the average. I've had some DRT's with the 270 but a lot more with the 300.
That said, I'm switching to a 30-06 strictly for the weight. I just bought a Ruger American that weighs a lb less than my Savage 300 WSM. At my age, that pound adds up after a day of steep mountains. The recoil of the 300 in this light rifle would be more than I want to deal with. The recoil of the 30-06 in the Ruger is about the same as the 300 WSM in the heavier Savage. I'll likely stay with the same 180 gr bullets that I've used for years in the 300.
