Anything other than controlled load against load testing, is anecdotal crap. Testing correctly (scientifically), will require a lot of repetitions and a lot of testing. It will require a large supply of shot to shot consistent test media changed after each shot. Testing should be of an impact velocity at a normal hunting distance- IMO, something like 100 yards. Can't have factory ammo adjusted to expected velocity at a set range so have to set media at that distance and shoot into it. Can use reloaded ammo adjusted to average factory assumed muzzle velocity then loaded for expected impact velocity at the 100 yard distance with media test distance at about 5 yards from muzzle. This is what I do to test bullets. Reload to expected impact velocity at about 100 yards and shoot into media about 5 yards from muzzle. Select a decent sample size for each load- maybe 3 reps. Take consistent measurements for wound channel estimation, wound channel path and depth of penetration. Pick 3 common factory loads for both the 270 and 30-06 with different common bullet designs in different weights within the common weight ranges for both calibers. This is a lot of shooting, a lot of media resets with a refresh of media after each shot and a lot of measuring. It will take a lot of time. Post results. That will come closest to answering the basic question in the OP. Of course you have to compare apples to apples when reviewing the data. It should be obvious a slow 220 gr tough bullet out of the 30-06 is going to penetrate a lot more than a fast 130 gr frangible bullet out of the 270. But closer apples to apples... might be the penetration of a 150 gr 270 bullets of a particular design compared to a 180 gr 30-06 bullet of that same design. Three reps of each load and bullet weight and design for both calibers should be statistically valid enough to prevent too many "ya buts".
The arithmetic indicates a lot of shots
3 shots 130 gr 270 Bullet X
3 shots 130 gr 270 bullet Y
3 shots 130 gr 270 bullet Z
3 shots 150 gr 270 bullet X
3 shots 150 gr 270 bullet Y
3 shots 150 gr 270 bullet Z
3 shots 150 gr 30-06 bullet X
3 shots 150 gr 30-06 bullet Y
3 shots 150 gr 30-06 bullet Z
3 shots 165 gr 30-06 bullet X
3 shots 165 gr 30-06 bullet Y
3 shots 165 gr 30-06 bullet Z
3 shots 180 gr 30-06 bullet X
3 shots 180 gr 30-06 bullet Y
3 shots 180 gr 30-06 bullet Z
= minimum 45 shots
*add 3 shots for each different bullet design or weight tested