Why WW2 Bombers Eliminated Tracers In Their Ammo

Why did a majority of US bombers such as the B-17, B-24, and B-29 get rid of tracers in their ammo mixes? 

The Real Reason

At the end of the war, virtually all bombers were using armor-piercing incendiary cartridges as the ammo mixes.

Although tracers are highly effective when looking for targets in ground fighting, they’re relatively less useful on planes because of the relative speeds that are involved.

What’s Wrong With Tracers?

The issue with tracers, or the bullets themselves is that under the right conditions, the contrail the bullet leaves is often the part you see well is the part that’s closer to you. 

In the case of a machine gun, the closer rounds would usually overwhelm one’s ability to see at a greater distance.

Gunners would start watching their tracers rather than the gun sites. However, tracers won’t give a true indication of where the bullets are actually going. 

Better Technology

Later in the war, gyroscopic computer models were introduced which helped adjust the aim point for drop and lead, thus, significantly decreasing the value of tracers.