They were tracers, marked with a red tip, and did light just fine when fired downrange, just like all the others I've fired. They were just being fired at too close a distance to light when we were shooting them. If you are shooting them up close, and walk up close to the berm right after shooting them, you can often hear them cooking off in the dirt though.
Tracers, or at least military tracers are designed to light downrange, and not at the barrel. It also makes sense if you think about it. Its bad enough they are lighting 50-75 yards out, but thats still better than drawing a line straight back to the muzzle.
For other than military, or some very specialized uses, or just fun, tracers are pretty much just a waste of money, and especially the premium they seem to draw at the gun shows. I think too much of the sales pitch and perceived use is based on old war stories than real world use of them.