Does the .308 offer better terminal ballistics than .270 for whitetails?

Bullet Penetration and Expansion

When it comes to terminal ballistics, bullet penetration and expansion are crucial factors to consider for whitetail hunting. The .308’s heavier bullets, often weighing 150-180 grains, tend to penetrate deeper into the deer’s body, increasing the likelihood of a clean kill. In contrast, the .270’s lighter bullets, usually 90-130 grains, may not penetrate as deeply, potentially leading to more shots being required to harvest the deer. A study by the Ballistic Research Laboratory found that a .308 Winchester 150-grain bullet penetrates an average of 18.5 inches into the deer’s body, while a .270 Winchester 130-grain bullet penetrates an average of 12.5 inches.

Kinetic Energy and Trajectory

Another key factor in terminal ballistics is kinetic energy, which measures a bullet’s ability to cause damage upon impact. The .308’s heavier bullets typically have a higher kinetic energy than the .270’s lighter bullets, even at longer ranges. This is due in part to the .308’s flatter trajectory, which allows the bullet to maintain its velocity and kinetic energy over a greater distance. For example, a .308 Winchester 150-grain bullet retains 75% of its kinetic energy at 400 yards, while a .270 Winchester 130-grain bullet retains only 50% of its kinetic energy at the same distance. This means that the .308’s bullet will have more energy to transfer to the deer upon impact, increasing the likelihood of a clean kill.