Those sound like Remington 158g SP's, or Winchester 158g SP's. Either of these bullets will definately expand at revolver velocities, and perform extremely well as far as a perfect mix between expansion, and penetration from a rifle barrel. They do "not" perform like hard cast's
. They don't mushroom violently like a HP, but they do expand on a deer, or other 50 lb or bigger critter.
It's possible that they're not Remingtons, or Winchesters, but I'd say they're still in the ball park as far as performance.