Can a Bullet Really Start a Fire?

September 25, 2008

Question: I have been a hunter and target shooter for more than 50 years. I’ve heard different agencies blaming fires on sparks caused by bullets striking rocks. I was not aware that lead and copper would cause sparks. Am I missing something or is this more hype to discourage hunting and target shooting? (Charles M.)

Answer: It is not necessarily the bullet itself but the object contacted that can cause ignition. Fires caused from target shooting could be due either to bullets striking a rock with the geological potential to spark just right or shooting at metal targets that have the potential to start a fire.

Rifle range, Junction City, off Hwy299.

O.K., what rocks have the 'geological potential' to spark when struck? (not just flash, but a sustained spark that can ignite tinder) My understanding of using rock to start a fire is that you need some high carbon steel and a rock that is harder than high carbon steel.  Strike the steel to the rock, causing fragments of steel to shed off and ignite due to the friction.  It's the steel, not the rock that sparks. 

The comment about bullets striking metal targets and starting fires has NOTHING to do with the question.  It's simply there to distract from the story about rocks having the potential to spark when struck. 

O.K., what rocks have the 'geological potential' to spark when struck? (not just flash, but a sustained spark that can ignite tinder) My understanding of using rock to start a fire is that you need some high carbon steel and a rock that is harder than high carbon steel.  Strike the steel to the rock, causing fragments of steel to shed off and ignite due to the friction.  It's the steel, not the rock that sparks. 

Flint and pyrite will spark when struck with steel.

Friction causes heat. The round striking a solid object causes the bullet to deform. Copper is nonferrous and will not spark. Copper will get hot. A bullet striking a solid target like a rock or steel target can cause the bullet to fragment. The impact from the bullet creates friction and generates heat. The copper fragment may be red hot, and ignite suitable materials around the area. Not likely, but can and has happened. Shoot a bullet into a thick steel plate, and then go recover your bullet, it is hotter than hell! Part could be from the powder ignition, but I believe the majority of the heat is caused by the molecular motion of the atoms in the bullet distorting upon impact. Take a ricochet, it may shave off a sliver that is guaranteed to be hot because of the friction between the bullet and the target, but is there enough combustible material around, and is it going to cool before it can ignite? Then there is tracer ammo........

my many years in the Marine Corps and many thousands of roundr.
the only fires i have seen,
come from tracer and armour piercing wich have a tungsten core

my many years in the Marine Corps and many thousands of roundr.
the only fires i have seen,
come from tracer and armour piercing wich have a tungsten core

Same here.

I always thought the concern was with steel core ammo primarily. Least we not forget Frogbat!

   

So, what do you suppose is going to happen when California mandates steel ammo for hunting all game?  I would guess that a whole lot of fires are gonna be blamed on gun fire.  Which will lead to what...  a ban on firing ammo during high fire seasons regardless of what game may be in season.  Maybe even being illegal to take a gun into the field during those times. 

Steel core is a bad idea all around, but especially in the humid climate here. The bullets they have now for "condom country" are mostly copper. Some have tungsten cores, but it shouldnt change anything compared to say Remmington Core-Lock ammo as far as sparking. Fragmenting, yep, but sparkability? No. Copper is just not sparkalicious.

Rich way is steel core bad? I go through a lot of surplus steel core and wolf import and don't seem to have problems from humidity.

For hunting it is illegal, and if there is a chance of moisture getting into the projectile, electrolosys (SP?) can delaminate the core from the jacket, and you get in air separation, or unreliable performance on impact. For plinking and target shooting you will be fine.

Once at a firing range the accumulation of "stuff" at the back of the range caught fire while we were shooting. 

Once at a firing range the accumulation of "stuff" at the back of the range caught fire while we were shooting. 

I've seen some folks put "stuff and things" in back to catch fire and "stuff", too!