My wife tried the 120gr Pro Hunter a couple of years ago on antelope in her 7mm-08. She shot her buck three times in the heart/lung area at between 200 and 300 yards. You could cover the group with your hand.
Not one of the bullets penetrated the off side. The three shots combined to make one single entry wound looked like an exit wound. You could have poured the goo that remained of the heart and lungs out of the entry wound except for the fact that the ribs got in the way.
She switched to Nosler 120gr BT's for the following years hunt. Bang. Flop.
We relegated the Sierras to pre-season paper practice.
To answer your question, they do not penetrate. They blow up.
