There are actually three generations of Grand Slams, the originals (which were tender), the middle generation (made up until about 2-3 years ago, which worked great), and the latest.
The middle generation always worked fine on everything I tested it on, whether animals or any sort of test media. They acted very much like Nosler Partitions, both in retained weight and how wide they expanded.
In dry paper, Hornady Interlocks will generally hold together, though sometimes you find the jacket and core side-by-side. But they peel back a lot further than bullets like the Partition and the middle-generation Grand Slams.
That said, I have never had one come apart at the ENTRANCE hole on game, as has happened on a few occasions with standard cup-and-core bullets. On deer-sized game, I am far more worried about that sort of separation, than finding both core and jacket slightly apart on the FAR side of the vitals.
Also, of course, how well the Interlocks hold up depends on size and impact velocity. But I have generally had very fine luck with them on all sorts of game, in calibers from .25 to .375, given some reasonable care in choosing the right bullet and cartridge for the job.
JB
