I've had very good results with the Accubonds in .257, .270, and .300 Weatherby calibers. The penetration was deep, but the bullet will shed it's forward portion. Weight retention has consistently been between 55-60% of original weight. This was true using a 110 grain Accubond at 300 yards, a 140 grain Accubond at 85 yards, and a 180 grain Accubond to 180 yards.