IMO, shedding a core does not make it a tough bullet. Especially a 200gr on deer.
Just differing definitions of tough.
CRS,
You're free to define it however you want.
I tend to regard any big game bullet as pretty tough if it consistently penetrates deeply enough to kill pretty big animals, regardless of whether the core leaves the jacket or "petals" break off.
I have killed, and also seen killed, a bunch of big game with the heavy-jacket Ballistic Tips. The first introduced was the 200-grain .338, because Nosler realized some people would hunt game larger than deer with them. The .338 was successful enough that later Nosler turned all the Ballistic Tips from the 165 .30 into heavy-jacket models, meaning the jacket was the majority of the bullet's weight. I have used several of them, not just the .338, and so have friend.
The one I shot lengthwise through the bull gemsbok is the only one recovered from all the animals I've personally killed with heavy-jacket Ballistic Tips, but friends have also recovered a couple. One was another 200 .338 a local friend used to kill a cow elk, which was angling away at around 200 yards. He had to place the bullet a little higher than usual, because the elk was standing in brush. It landed in the lower part of the left shoulder blade, broke the spine, and then went through the far shoulder just above the big joint. The jacket was found under the hide of that shoulder.
The other recovery was a 180-grain .30 that another local friend used to kill another mature cow elk. He'd handloaded it in a .300 Weatherby, and the cow was standing facing him directly, as I recall at around 250 yards. At the shot the elk collapsed, because the bullet had gone through the bottom edge of the spine. He found the empty jacket under the hide of the rump.
Have also seen heavy-jacket Ballistic Tips break both shoulders of 500-pound animals and exit, both in North America and Africa. Have also recovered various monolithics and other "controlled expansion" bullets that lost considerable weight from suddenly dead animals. These bullets have included a 130-grain TSX from a .308 Winchester that broke the near shoulder of a quartering-on cow elk my wife killed a couple years ago--the biggest cow either of us have ever taken, as large as many mature bulls. The range was about 250 yards, and at the shot the elk staggered 20-25 yards, obviously dead on its feet, before collapsing. The bullet broke the near shoulder just above the big joint, went through both lungs, and was found under the hide in the middle of the ribs on the other side. It only retained 61% of its weight, due to losing ALL of its petals.
Another example was the 150-grain Nosler Partition Eileen used from a .270 Winchester to kill a medium-sized Shiras moose. This was not a giant moose, but still probably weighed more than 800 pounds on the hoof, as large as any big bull elk I've seen on the ground. The moose was quartering away to the left at about 125 yards, and the bullet entered the middle of the left ribs The bull took a step and a half and folded up, dead. We found the bullet under the hide next to the right shoulder, where it stopped after penetrating around three feet of moose. It only retained 54% of its weight, the lowest percentage of any Partition I've ever recovered, yet somehow killed the moose not merely dead, but really most sincerely dead. That was 31 years ago, and despite having seen quite a few other moose taken since then, is still the quickest-deadest bull shot with any bullet and cartridge--and the cartridges have ranged up to .375 H&H.
Those are just a few examples of big game animals taken with bullets that did not retain even 2/3 of their original weight, yet died quickly, because the bullets penetrated completely through the vitals, despite not exiting. Have also seen plenty of big game animals stay on their feet a lot longer after being center-punched through the heart/lung area with bullets that did exit. The last was a big mule deer doe I killed last fall at around 200 yards with a 140-grain TTSX started at around 2850 fps from a 7mm-08. The bullet landed right where I intended, just behind the shoulder about 1/3 of the way up the chest, yet the doe ran just about exactly 100 yards before falling.
I have also shot two buck deer, one a mule deer and the other a whitetail, with cup-and-core bullets that shed their cores at the ENTRANCE hole--yet somehow the bullets still killed the deer on the spot, because the core kept on penetrating, because in standard cup-and-cores the lead weighs more than the jacket. The mule deer was angling away at about 100 yards, and the bullet was a 130-grain Sierra GameKing from a .270 Winchester. At the shot the buck collapsed and didn't move, and when I skinned it later that day I found the jacket just inside the entrance hole, and was was left of the core in the opposite shoulder. The whitetail was broadside at around 200 yards with a 105-grain Speer Hot-Cor from a .243 Winchester. It also collapsed and never moved, despite the jacket again being found lying against the ribs at the entrance hole, because the core kept going and broke the spine.
Have also seen bullets that retained at least 90% of their weight fail to exit deer-sized animals, all of them retaining their cores because they were bonded. This is because some (not all) bonded bullets open very widely, which reduces penetration considerably.
All of these examples, along with others, are why I quit worrying a long time ago about whether some bullet doesn't retain at least 90% of its weight, or loses the jacket or all its petals, or exits--as long as it consistently penetrates through the vitals.
Obviously this is just an opinion, as is calling the 200-grain .338 Ballistic Tip a "pretty tough" bullet, but it comes after observing the results from close to 1000 big game animals.
