I was fortunate enough to spend a significant portion of my research time working on non-incendiary tracer rounds for the US ARMY. The original tracers were known as “Glow Ammo”. Cabela’s now sells them as G2 Research VIP Cold Tracers
The problem with the original tracer rounds is their inaccuracy. Tracers loss mass as they burn during flight. The often results in them hitting below the desired target, which is ironic because the point of the tracer is to have visuals of where your munitions are hitting at night. To solve this we develop tracers that wouldn’t loss mass during flight. We also built a dark tunnel to shoot and test our munitions that the Lafayette Parish Sheriff’s department now uses for training.