Frangible ammo sparking

[gunnut284]

We were shooting steel plate in dark conditions in the indoor range to other yesterday and noticed considerable sparking when hitting the plates. We hadn't noticed the sparking before and the rangemaster is concerned about a possible fire hazard when shot into the rubber lines backstop. Anyone have knowledge on the cause of the sparking (we were shooting a different brand of ammo than usual) and the possibility of a fire risk?

Edit: I just heard back from the rangemaster and apparently the ammo wasn't truly frangible.

[SIGguy229]

What would be volatile-enough on a range backstop for a small spark to ignite into a fire? As far as frangible ammo sparking--static discharge from the compressed metal striking the steel?

[gunnut284]

The concern was the rubber in the backstop and possible built up powder residue. A local commercial range (Gander) had a backstop fire a few years ago. I believe due to tracers though. The amount of sparks just got him worried.

[SIGguy229]

With tracers, the concern is warranted; there is an accelerant. But static or friction sparks, there would need to be an accelerant to start a fire. BTW--I'll bet if he turned down the lights and shot FMJ, he's still see sparks--it's metal striking metal.

[Ron3]

Bullets are weird sometimes. The other day I was shooting .25 acp fmj at a brick (at an angle). Three hits and it only chipped the brick each time.
However one shot resulted in an obvious spark. Copper/zinc jacketed lead .25 bullet sparking off a brick? Dunno why but it did.

(Not a cool story, bro. Just something I recently observed)