Does Ammo Expire? A Clear, Evidence-Based Guide

Yes, ammunition can expire or degrade over time, though proper storage often extends usability and reliable function. The core components—case, primer, powder, and projectile—are affected differently by age, environment, and handling. Centerfire cartridges typically last longer than rimfire ammunition, and many well-maintained rounds remain safe and accurate for decades. However, deterioration can progress quietly, affecting ignition, pressure, and accuracy. This guide explains the main factors, realistic timelines, inspection steps, and best practices so you can determine whether your specific ammo is still reliable.