Time to answer some reader mail.
“I enjoyed your post on derringer’s, but had heard that shorter barrels increased barrel flame. Is this going to be a problem if they are shot indoors?”
Do guns emit vast jets of flame when fired? Certainly seems so if you go to the movies!
(Picture source.)
My goodness! It is a wonder that they don’t catch the entire neighborhood on fire!
Muzzle flash is exciting in the movies, which rely on visual cues to indicate drama and conflict. Many times the flash is added in post production as a computer image laid on the film. Average guns loaded with normal ammunition don’t look like that under normal lighting conditions.
Okay smart guy, so what does it look like?
Notice the blue-grey smoke coming out of the front of the gun? If the guy doing the shooting was under low light conditions, and your eyes had adjusted to the dark so they were taking in as much light as possible, then you would see a flash of light every time he pulled the trigger. But keep in mind that it has to be rather shadowy for you to see anything at all.
Here are two pictures of a handgun at the moment of being fired. Notice that the muzzle has jumped, and the action is cycling.
(Picture source.)
Hey, where is the muzzle flash? It is there, but the shooting range where these were taken is much too bright to be able to see the dim and murky pop of yellow light that briefly appeared in front of the barrel.
So the muzzle flash isn’t as impressive as Hollywood would have us believe. Can guns cause fires anyway?
Well, I suppose it is possible, I’m just not sure how to go about igniting anything with a muzzle flash. The American writer Mark Twain relates how he and his companions tried to set a campfire alight with one of their guns in the book Roughing It, and I doubt I’d have any better luck. If anyone has any ideas, I’d love to hear them.
So, bottom line, I wouldn’t worry too much about a muzzle flash setting the house on fire.
I think maybe a black powder blank load with some tissue paper closing the shell would be your best bet. All that hot ash from the black powder might be able to transfer enough heat to the tissue paper to catch it on fire, so just shoot from several feet away into your prepared tinder where you want your fire and hope for the best. Shoot from too close and the muzzle blast is going to scatter your tinder everywhere, too far away and all the heat is going to go into the air and dissipate.
Smokeless powder generates lots of hot gas, but once it leaves the muzzle it immediately dissipates into the air before there is time to transfer that heat into anything.
I understand the easiest way to start a fire with ammo is to use bullets with steel cores and shoot rocks with dry grasses growing around them. The steel core generates lots of sparks when it hits the correct kind of rocks and sets the vegetation on fire. Happens several times a year in the west with people shooting cheap military surplus rounds.
The movies use specially prepared blank rounds to get that effect. Of course, the weapons have barrel constrictors so they can fire full auto with blank ammunition, but the blank rounds are salted with petroleum mixed into the propellent powder so that they’ll make that flare when they go off.
Just in passing, if real weapons did that, it would be a sign of bad design. First, it means you’re wasting propellant. Second, it makes it easy for enemies to tell where you are.
If muzzle flash was always as bright as the movies made it out to be, the people shooting the weapons would have problems seeing their targets (Or much of anything while they are shooting.).
They say, “Tracers work both ways” and this would be even worse.
This muzzle flash looks rather bright from the side (though not as bright as the theatrical blanks), but it’s almost impossible to see when firing the gun.
M44 Muzzle Flash: http://youtu.be/9PLqUh15SJw
Those blanks make a foul mess in the bore, in my experience.
Here is muzzle flash,
http://commons.wikimedia.org/wiki/File:Missouri_broadside.jpg
I think you found a muzzle flash that might actually be able to start a fire!
Cover photo for ‘Stressfire’ by Massad Ayoob.
http://www.amazon.com/Stressfire-Vol-Gunfighting-Police-Techniques/dp/0936279036
I *believe* this was night-time photo with one of the older loadings of the .357 magnum round out of a short barrel.
The exposure on Mas’s “Stressfire” is a time exposure so it catches the flash as is moves outward from the gun. It’s a posed photo and I’m sure it was chosen for max impact.
I attend a demo by Ken Hackathorn on the color of muzzle flash at night several years ago. The flash was so brief and of such low intensity you could barely see them and if you blinked, it was gone.
Ah. That makes sense, and it certainly has impact.
A rolled up cylinder cylinder of cotton cloth with a char cloth core fired with a small powder charge in a blackpowder muzzle loading fire arm would give you a good source of ignition for tinder. Fires a sometimes started by the smoldering cloth patch from muzzle loading rifles landing in dry grass.
I’m sure most of us have seen pictures of the way the California desert will bloom after the (infrequent) spring rains. A couple inches of rain and the seeds that have laid dormant for years will spring to exuberant life. The desert valleys are a solid carpet of wildflowers.
They bloom, go to seed, and then die back. A couple weeks after the rains, everything is dead and brown and bone-dry.
Saw this happen at Ft. Irwin a few years ago when I was there. One training rotation, up at the live-fire range was a solid carpet of flowers. A spectacular sight. Next rotation, three weeks later, the life cycle was completed and everything was brown and dead and very dry.
You would drop to a prone position, fire a burst from your weapon, and as soon as you let go of the trigger you would see the little flames spring to life. And grow, and spread.
Eventually, of course, we lit up the entire valley, and it got kind of spectacular for an hour or so. Then everything burnable had burned off and things went back to normal.
So, yes. If it’s hot enough and the vegetation is dry enough it is perfectly possible to start a fire with just the muzzle flash. M-16’s some of the time, but every time the M-60 machineguns fired, they started a fire. Every time.