Jerseyboy,
Actually, I doubt if Phil used the words "stopping rifle" but yes, he did start out as a brown bear guide with a .30-06 and 200-grain Partitions many years ago, because that was the rifle he had, and 200-grain Partition were, at the time, probably the deepest penetrating .30 caliber bullet.
The combination kept bears off him, but there were too many adventures involved, the reason Phil eventually bought the Mark X Mauser .458 Winchester Magnum that he turned into Old Ugly. It is still his favorite stopping rifle, despite him having used a bunch of other rifles and rounds, because it provides the right amount of power in a comparatively lightweight rifle.
Aside from reading Phil's writings (I have even published some in both magazines and on the Internet) one point he made was that the advantage of a "stopping rifle" wasn't that the cartridge was powerful enough to always stop, finally and forever, a charging brown bear with one shot. He has apparently never found such a round, despite experimenting for decades with cartridges up to and including the .505 Gibbs.
Instead what he found was that larger cartridges would often stop (or even drop) charging bears at least momentarily, even if the hit wasn't instantly fatal, providing time to get in another shot--often on a stunned and stationary bear, rather than a bear often running through thick brush. That was the flaw with the .505: While it stopped bears even with non-fatal hits, the heavy recoil made follow-up shots slower. All of which is why Old Ugly is still his favorite--and the rifle he took to Africa recently on his first Cape buffalo hunt.
He does prefer bullets that penetrate well, even at odd angles and through heavy bones, because you can't always count on a central nervous system hit on charging bears, especially in brush. Which is why he has experimented considerably with bullet penetration, once even on a dead whale that washed up on a nearby beach. During those experiments he found the 220-grain Nosler Partition penetrated deeper than any other .30 caliber bullet he tried, including monolithics. There's no doubt he would have used the 220 when he started in preference to the 200-grain Partition--but the 220 did not exist then. He did use 220 a few years ago when, for various reasons, he again ended up going after a wounded brown bear with a .30-06. It worked--but not like Old Ugly.
