Can Over- crimping Harm Bullet Performance?

The Effects of Over-Crimping

Over-crimping occurs when the crimping die is applied for too long, causing the bullet’s jacket to be compressed beyond its intended limits. This can lead to a reduction in the bullet’s diameter, resulting in a tighter-than-intended fit in the chamber. When the cartridge is fired, the excessive pressure can cause the compressed jacket to stretch or even break, leading to a loss of velocity and accuracy.

Measuring and Controlling Crimp Depth

To avoid over-crimping, it’s essential to measure the crimp depth and control the amount of pressure applied. A good rule of thumb is to aim for a crimp depth of 0.002-0.003 inches (0.05-0.08 mm) for most hunting bullets. This can be achieved by using a crimp gauge or a depth micrometer to measure the crimp depth. It’s also crucial to use a consistent and gentle touch when crimping to avoid over-compressing the bullet’s jacket.

The Importance of Bullet Design

The design of the bullet itself can also play a role in its sensitivity to over-crimping. Some bullets, such as those with a thicker or more rigid jacket, are less susceptible to over-crimping than others. In general, it’s best to choose bullets that are designed for the specific application and cartridge, as these are often optimized for the intended use and are less likely to be affected by over-crimping.