Noise effected by barrel length?


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KJS
July 13, 2010, 04:19 AM
Someone with vastly more firearms experience than my novice level told me that a shorter barrel (all else being equal) will produce more noise.

Is that accurate? If so, I'd rather not hear what a snub nose .357 sounds like, since my 6" barrel is anything but quiet.

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TwoNiner
July 13, 2010, 04:32 AM
More muzzle flash perhaps, but noise? I believe thats dependent on how much powder is in the case.

bskillet
July 13, 2010, 04:38 AM
Off the top of my head, I'd say maybe, but not in a big way for a handgun. The sound is caused by rapid expansion of gases as they hit the air. Suppressors work by giving the gases a place to expand without hitting the outside air. If your barrel is longer, the gases have more room to expand, kind of like a suppressor. But I doubt the effect would be that great.

Oyeboten
July 13, 2010, 04:44 AM
A shorter Barrel Pistol has the escape of the high pressure gasses occurring a little closer to one's Ears.

I doubt that a test for decibles would show any difference, even though in theory, same Cartridge in a short verses long barrel, Gas pressure at escape may be a little less in the Long Barrel.

LawofThirds
July 13, 2010, 04:50 AM
It's not more noise, it's just closer to you and combined with the flash from the larger amount of unburned powder, it feels bigger.

Honestly, with earplugs, I can't tell much of a difference.

KJS
July 13, 2010, 05:20 AM
It's not more noise, it's just closer to you and combined with the flash from the larger amount of unburned powder, it feels bigger.

Honestly, with earplugs, I can't tell much of a difference.

I've never yet been able to see any flash when firing a gun, but then I do so on an indoor range and I'm behind it, so I don't get a side view that would clearly reveal how much muzzle flash there is. I've never fired in darkness where it would probably be hard to miss a muzzle flash that lights up the night.

LawofThirds
July 13, 2010, 07:02 AM
I've found it's easiest to see muzzle flash on an indoor range, especially if you have the chance to turn the range lights off. I think the most impressive one that I've gotten has been blue dot under a 185g SWC in a M&P 45 compact. The slower burning powder combined with the short barrel really put out alot of light and smoke (and little burnt blue dots all over the gun, my arms, the partitions, and everything else in a 10 foot circle which is why I retired that loading).

Deus Machina
July 13, 2010, 07:34 AM
I do swear that a snub-nosed .357 puts out more noise than a long-barreled one due to the extra powder, but it could also be from the air moving out of the way faster, or just being less directed, or just having a higher-pitched report or something.

I can attest, as a fact, that my 5.5" Ruger is often very much louder than a friend's mother's Taurus 22B (2.5" barrel), and for the same reason any other gun may be, within the same caliber--my Ruger has enough barrel to get some ammo into the supersonic range.

That Taurus, with soft target rounds, can actually be on the quiet side.

madcratebuilder
July 13, 2010, 09:56 AM
I recall seeing a test for noise levels using a DB meter, there was a slight increase on short barrel revolvers shooting the same load. It was more pronounced in rifles.

CraigC
July 13, 2010, 01:33 PM
Absolutely! Honestly, I can't believe there's this much discussion about it. It is more pronounced in rifles but certainly present in handguns.

DoubleTapDrew
July 13, 2010, 04:56 PM
Fire a 16 or 18" AR-15 then a 9" or 10" one. Wear earplugs! You'll feel the difference.
In a less extreme example my 3" .22 is noticeably louder than the 5".

Atticum
July 13, 2010, 05:50 PM
Absolutely! Honestly, I can't believe there's this much discussion about it. It is more pronounced in rifles but certainly present in handguns.
CraigC has it. There's definitely a difference.

And if you can't see the muzzle flash from a .357 revolver when you are shooting it, stand in the next lane over while your buddy shoots it for you.

:evil:

Owen
July 13, 2010, 06:32 PM
its dependent on the pressure of the gases when the bullet uncorks. A longer barrel will have less pressure when the bullet exits.

And, if you can't see the muzzle flash from a .357 while your shooting it, stop closing your eyes.

Confederate
July 13, 2010, 09:53 PM
I think it's more a perceived thing than real. Shorter barrels produce more blast and that blast and recoil make one think there's more noise, or at least it accentuates the noise. So yes, while there is a slight noise increase, it's accentuated by the blast and recoil of the shorter barrels.

Now shooting a .357 inside a car...well, I'd hate to have to do it! I remember in one of The Sopranos episodes where one guy shoots another in a car. You see the blasts, you hear them, and then the shooter gets out of the car and runs off. It was pretty dumb. One good way of catching him:

Cop: "You're under arrest."

Shooter: "WHAT?"

Cop: "YOU'RE UNDER ARREST!"

Shooter: "YOU WANT MY DRESS??"

Cop: "Aw...COME ON!"

No mob guy would be that dumb. But Hollywood writers are.

jhvaughan2
July 13, 2010, 11:15 PM
And, if you can't see the muzzle flash from a .357 while your shooting it, stop closing your eyes.

This.

When I shoot .357, indoors, from my m19 snub I have to reacquire the target after the flames recede. (One reason this will never by my choice for home defense.)

CraigC
July 14, 2010, 02:41 AM
I think it's more a perceived thing than real.
Hogwash! It's blatantly clear just comparing a 16" .22LR to a 24" or longer. There is NO blast but the noise is clearly louder with the shorter barrel. It's the speed of the escaping gasses. Longer barrels have a greater volume of space for the gasses to expand and slow down. Think about what a suppressor does. A very long barrel has the same effect, just to a lesser extent.

springfield30-06
July 14, 2010, 09:43 AM
Hogwash! It's blatantly clear just comparing a 16" .22LR to a 24" or longer. There is NO blast but the noise is clearly louder with the shorter barrel. It's the speed of the escaping gasses. Longer barrels have a greater volume of space for the gasses to expand and slow down. Think about what a suppressor does. A very long barrel has the same effect, just to a lesser extent.

I was just thinking yesterday about why my 5.5 inch Ruger mkIII sounds louder than my 16 inch Ruger 10/22. There is a difference but I wasn't sure of what makes the shorter barrel sound louder.

Sam1911
July 14, 2010, 11:11 AM
The best possible answer to this thread is probably THIS thread: http://www.thehighroad.org/showthread.php?t=31394

Discussion of the Metrogun barrel extension for shotguns.

http://www.metrogun.com/images/PR05161075801.jpg

Long extensions to increase barrel length by several feet. Claim to drop the sound level of subsonic shotgun ammo to less than 72 db. No baffles or ports (not a suppressor/silencer) just extra barrel length/volume.

(http://www.metrogun.com/)

Oyeboten
July 14, 2010, 05:47 PM
This is the 'Revolver' section...OP's question was with respect to Revolver Barrel lengths.


Pressures and or Volumes of Gas will be greatly smaller in Revolvers generally, than in Rifles or shotguns, of course.

I imagine most Ammunition for Revolvers assumes a mid length Barrel or a longer rather than shorter Barrel, far as powder type and Gas volume realized in relation to Bullet weight-resistence.

How this would co-relate to pressures at various lengths as the Bullet exists, could be all over the board...as would the report, even if all Reports seem 'loud'.

Black Powder in say 45 Colt Cartridges, gives a very good report in a Snubby or a long Barrel, and does so at what is likely 9 to 12 thousand PSI...far below usual smokeless pressures.

So pressure alone is not likely as much of an issue for decibles generated, as volume of Gas is of a given pressure.


Shorter Barrel Revolvers, the end of the Barrel is however much closer to one's Ears and face, than longer Barrels...and that has to make a little difference anyway! Whatever else is going on...

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