Is there a difference in terminal ballistics between 150gr and 165gr?

Bullet Expansion and Penetration

In the .308 Winchester, a 150gr bullet typically expands to a diameter of 0.625-0.65 inches, while a 165gr bullet expands to a diameter of 0.7-0.725 inches. This increased expansion of the 165gr bullet can result in deeper penetration, potentially increasing the effectiveness of the shot on larger deer or those with dense bone structures. The increased mass of the 165gr bullet also contributes to deeper penetration, as it is able to transfer more energy into the target.

Ballistic Coefficient and Wind Deflection

The ballistic coefficient (BC) of a bullet affects how it interacts with the air during flight, with higher BC bullets being less affected by wind deflection. A 150gr bullet typically has a BC of 0.415-0.435, while a 165gr bullet has a BC of 0.45-0.465. This means that the 165gr bullet will be less affected by wind deflection, allowing for more accurate shots at longer ranges. However, this increased BC is not necessarily a decisive factor in the choice between the two bullet weights for deer hunting.

Practical Considerations for Hunting

When choosing between a 150gr and 165gr bullet for deer hunting in the .308 Winchester, it is essential to consider the specific hunting situation. If you are hunting in thick cover or for smaller deer, the 150gr bullet’s faster expansion and lower penetration may be beneficial. However, if you are hunting in open country or for larger deer, the 165gr bullet’s deeper penetration and increased expansion may be a better choice. Ultimately, the decision comes down to personal preference and the specific needs of the hunt.