Anecdotal, yes - but close to home: 170gr Nosler Partition Round Nose (specifically designed for the 30-30) and down-loaded in a .308 for hunting in close cover (to keep impact velocity below ~2,300 fps).
Impact velocity on this bear was about 2,100 fps. Bullet penetrated completely from broadside. Bear made a wild, confused dash and piled up. This was essentially a "30-30" shot at about 25 yards (it was a downloaded .308 at 50 or so).
The bear was moving as it had been kicked up by another hunter, so not exactly calm.
As stated earlier, this has happened countless times with the 30-30 and similar powered rounds, when the hunter does his part.
Make a poor shot and all bets are off (regardless of caliber).
The great thing about using something like a 30-30 (or a bow, or a handgun, or a single-shot) is it tends to focus the hunter on the fundamentals. You know you have to get closer and make great shot placement.
Fellow in the photo is 6 feet even and slightly in front of the bear, for scale.
