There have been three iterations of Speer GS.
The first had a hard rear core with a softer one ahead of it (no partition). The core was held by what they called heal crimp. At the base of the jacket, there was a hollowed out area that when the core was swaged in, filled this void and was supposed to keep the core from slipping forward. In my experience it only partially worked. I took a hog with a .30/06, using the 165 gr GS. When I found the bullet against the far hide, it looked like a perfect mushroom. However, when I picked it up, the core fell out. If I remember it had about 70% weight retention.
The second version also incorporated the dual core design but they added a ring inside the jacket which protruded into the core, similar to Hornady’s interlock. I took two elk and a mule deer using the 250gr out of a .338 WM. The bullet made exit on both elk, taking out at least shoulder on each. The huge mule deer, bullet broke shoulder, thru heart, exited the far ”armpit” and broke up the leg, lodging there. Front end mangled but still retained 74% weight.
The current version is like the second except it only has a single alloy core. I don’t have experience with this version. I appears to be like a Hornady Interlock with a heavier jacket.
