What challenge do gunners face when using tracer ammunition?

Gunners face a significant challenge of loss of the surprise element when using tracer ammunition because tracers produce a visible trail of light that follows the projectile through the air. This visibility allows both friendly and enemy forces to see where the rounds are going, thereby compromising the gunner's tactical advantage. The enemy can track the trajectory and conclude the gunner's position, making them vulnerable to return fire. This aspect of tracer ammunition affects the element of surprise in combat situations, as it eliminates the ability to fire without revealing one's location.

Other factors, such as reduced fire rate, increased barrel overheating, and higher ammunition cost, may have relevance to the overall discussion of ammunition types, but they do not directly address the core issue related to the tactical implications of visibility in combat engagements with tracer rounds. The primary concern remains that using tracer ammunition inherently signals the gunner's intent and position, which can be exploited by adversaries.