How true is this?

[sksvlad]

I found this passage about WWII tracers.
In their guns, fighter planes loaded every fifth round with a glowing tracer to help them aim correctly. This turned out to be a big mistake, since tracers took a different flight path than regular bullets–if your tracers were hitting their target, odds are 80% of your regular rounds were missing.

 

[pzgr40]

Fighters often used no tracers at all, but explosive bullets (BVIIZ for the .303 with blue nose) as tracers gave away the fact that to the enemy they were being fired at. With explosive bullets, the firing plane as well as the receiving party knew they hit the target by means of bright blue flashes on the target; when missing, the target did not know he was being fired at.

 

[HAZORD]

The best way to confirm your question, other than providing real info about their performance from a government study, is to compare the beginning weights of the different projectiles, compared to the weights of the tracers after they burn and add in how much the tracer adds to maintaining velocity by filling in the vacuum behind the projectile.

The majority of 50BMG ammo carried by fighters for air-to-air and air-to-ground the U.S. were 4 armor piercing incendiary rounds followed by 1 armor piercing incendiary tracer round. They weren't using normal lead filled ball ammo and tracer ammo as used by infantry. The API (silver tip) and APIT (silver and red tip) rounds could penetrate locomotives and thin armor, along with airplane engines, and the incendiary aided in igniting fuels etc.

 

[beihan62]

I have read in various publication that pilots requested tracer rounds be added to the belts near the end of the belt so the pilot would have a visual indication he was low on ammunition,