I don't think Speer revised the jacket on the new Hot-Cors. Or at least it didn't look like to to me when I sectioned some.
The Grand Slam jackets always had a ring similar to the Hornady Interlock ring around the harder rear core to hold it in place. Instead they just quit using the twin cores, so essentially the present Grand Slams are Interlocks with single-alloy, softer cores.
