I need to do some ballistics/fire retardant testing with tracers for my company, but I have to ensure that they ignite.  I have M196 tracers but the website I bought them from says they are late 1960's/early 1970's surplus and "look for them to ignite about 200 yards out."  I tested some last night in our indoor 25 yard range with the lights off and could not see them ignite because it was so short.  I won't shoot these outdoors unless there is snow on the ground which there is not right now.  

M196 is supposed to trace from 75-500 yards

I also found M856 tracers I can buy that trace 90-875 yards

Will tracers still light if they impact my bullet trap at 25 yards and stop?

I'm trying to think of a way to make sure they are lighting without shooting them outdoors (fire hazard).

I've seen 7.62x51 tracers shot into MRAP glass at close range.  The tracer lit while it was stuck inside the glass.

The honest answer is some will and some won't.  You will have to test it out as I do not know what comprises your bullet trap.

I mag dumped 30 rounds of M856 into the sand 10 yards in front of me once (don't ask why) and noticed some of the rounds ignited and burned for about 1.5 to 2 seconds after kicking up from the sand.

First off tracers + indoor rangers should never be mixed unless specifically designed for it.

Second, I've seen M196 ignite 25-40 yards out, and that Vietnam surplus lights at a relatively high rate. My brother has a ton of that stuff, and at our 100 yard range 8/10 are easily seen.

Our steel bullet traps are designed to handle tracers, no problem on our indoor range, we are the manufacturer of the bullet traps.  I did test them again today and had video from the side, you can clearly see all 5 M196 tracers light off right out of the barrel, I just cannot see it as clearly from the shooter's perspective behind the rifle.

Nevermind, these work great.

So you build a tracer friendly bullet trap ?

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Can we see please?

Yes, all AR500 steel, nothing to burn

M196 tracer test in the dark

US tracers have an "igniter" layer that is lit initially by the burning powder.  This layer is supposed to provide a delay between firing and ignition of the tracing compound, but the precision of this delay is variable.  Some tracer models are supposed to light sooner than others.  

To answer the main question, YES, if the tracer is going to light, it WILL light, in the berm, on the ground, in a bullet trap, wherever it winds up.  

And as noted, INDOORS?  Unless the whole range is built specifically to handle tracers, DON'T DO IT.

Interesting; thanks.