Muzzle flash - what's the main cause?


Dollar An Hour
October 2, 2005, 01:35 PM
Is muzzle flash/noise mainly caused by barrel length or the caliber itself?

.357's are very loud when at the range compared to most of what's typically being shot, usually out of semiautos.

Is this due to the high-pressure of the .357? Because .38's seem much easier on the ears.

I've never fired at night, but have heard folks say there is alot of muzzle flash from a .357 as well. Is this true of a .38 +P for example? Or a .44 Special? Shorter barrels are going to be worse I assume.

What I'm wondering is why do so many guys choose a snubnose revolver for CCW or use it as their bedside gun or car gun - when a short-barreled revolver is so nasty indoors or at night when you're likely to need it? Don't semiautos have a big advantage here? :uhoh:

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October 2, 2005, 08:29 PM
Well now, these are all good questions.
As far as ammo/muzzle blast/flash & noise goes.
The bigger the barrel, the less of all these you will have in general.
Example: 8 3/8 barrel .357 Magnum will be generally calm cool and collected.
Same ammo in a Snubbie 2.5 inch tube will generally be loud & flashy.
The problem with using a long tubed gun for self defense is that...
number 1: It's tough to hide. (Is that a Long barrel in your pants, or are you just happy to see me)
number 2: It's not as manuverable (you won't want to be waving it around corners looking for a bad guy)
Now, as far as semi-auto versus Wheelgun.
In a panic situation, you pull out your snub and pull the trigger when confronted.
In a panic situation with a Semi-auto, did you load the first round in the chamber ? Is the safety on or off ? You won't be thinking about those things if you are in a panic.
I've actually heard stories about guys being shot just because they could not get the gun out of the holster (because they were in a panic mode).
Now add the fact of loading one in the chamber and a safety. That's why guys go with the wheelgun over the semi.

Just my opinion.


October 2, 2005, 09:09 PM
As a generalization - the more potent the round and the shorter the barrel - the more unburned powder will be exiting the muzzle - contributing to the ''fireball".

Longer tube gives more time for a burn and so marginally cooler and better burned powder at muzzle.

Brands and speeds of powders as you might imagine affect this.

The snub revo - if well maintained is all but foolproof - draw - pull trigger - bang!!!

October 2, 2005, 09:38 PM
It's all in the load. Case in point: The gun I own with the most muzzle flash is my Ruger (long barrreled) Blackhawk in .30 Carbine. The reason? Because factory loads for a .30 Carbine are geared toward a longer barrel than the one that I'm shooting with. The unburned powder burns outside the barrel, producing an impressive fireball. Now, I could experiment with loads that would perform better with less flash. These same loads would perform miserably in an M1 Carbine.

October 2, 2005, 09:40 PM
Slower powders, shorter barrels higher pressure rounds, lighter bullets all give more muzzle flash and blast .Powder companies have improved things by adding flash retardents.

October 2, 2005, 09:40 PM
I think all that flash blast and noise will help deter said badguy even more particullary if first shot is a miss. sort of besides shooting also launching fireball his way. but still prefer revolver for reason of simplicity reliability and potent ammo choices over semi auto. every semi auto I owned liked and disliked various ammo. every revo I have owned ate everything I could shove in it. just mho.

Dollar An Hour
October 3, 2005, 02:19 AM
Good info everyone, thanks for the replies.

So it looks like despite the flash & noise from snubbie revolvers, alot of guys still choose them for CCW or a bedside gun just because they're point & shoot. No safety, slide racking, etc.

But plenty of DA semiautos have the ability to chamber the 1st round then store the gun ready to go. It's just like a revolver from there with the DA 1st shot. No safety. I could see if we were talking about a SA semiauto being 'one more thing' to worry about.

Seems like you'd have the best of both worlds there - DA first shot, no safety to hassle with, capacity and flash/noise/recoil reduction of a semiauto. ;)

October 3, 2005, 08:28 AM
Hey Dollar an hour,
You're in Mesa ? :confused:
Remind me not to apply for a job at your place of employment. :eek:
Your name said it all. :D
I hope you at least get good benefits. :rolleyes:


Dollar An Hour
October 3, 2005, 10:27 AM
I hope you at least get good benefits

I got the screen name from the movie Napolean Dynamite. :p

October 3, 2005, 11:12 AM
Factors that affect *PERCIVED* muzzle blast, in my rough order of signifigance:

1) Barrel length.
2) Total powder volume vs caliber.
3) Speed at which powder burns (very slow powders ie .357 in a 2" bbl burns still at a terrific rate outside the bbl.)
4) Normal opperating pressure of the cartridge. Ie 30,000CUP vs 65,000CUP.
5) Powder composition, ie flash retardant.

October 3, 2005, 02:13 PM
It's a common misconception that muzzle flash is caused by unburnt powder exiting the muzzle and then burning.

In reality, the powder has completed combustion long before the bullet reaches the muzzle, even with the slowest of powders. Any unburnt powder expelled from the muzzle is simply unburnt powder and will be found lying on the ground in front of the muzzle. Even a very slow rifle powder will complete burning in the first six inches or so. Most hand gun loads will complete buring within the first inch. A notable example of an improper load in this regard was the factory 357 maximum load which used too light a bullet with too slow a powder so the powder was still burning as it went through the cylinder gap creating the top strap erosion problem that did not occur with a proper load.

Some of the combustion products of the burning powder are themselves flammable. They exit the muzzle at a high temperature and on contact with the air they combust. It is this effect that causes the muzzle flash.

With a shorter barrel, the combustion products will be at a higher pressure and temperature when they exit the muzzle and a higher percentage of them will ignite. (At each point in the exiting cloud you have to have the right ratio of air to powder gas and sufficient temperature for ignition, hence the effect can be pretty variable.)

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