Bullpups louder?

[Dr_2_B]

I'd like to hear from some of you with experience using bullpup designs. I am keen to have one but I have a lingering question about the noise. In a bullpup design, the action (or the place where the explosion sets the bullet in motion) is right at the shooter's ear. Granted, even on traditional designs, that action isn't far from his ear. But physics tells us the proximity to the ear is extremely important in measuring volume.

Of course most of us shoot recreationally using hearing protection, but I'm talking about employing the bullpup weapon an emergency when there's no time to use hearing protection. Those with experience, have you noticed a difference? Or does someone know of any research on this?

NOTE: It'd be great if we could avoid the argument that a person in a crisis won't care how loud the gun is.

Thanks all

 

[boricua9mm]

Never shot my AUG w/o ear pro, but I can tell you that a comparably sized 5.56 SBR is MUCH louder and much more blasty than the 16" barreled AUG.

I don't notice it to be any louder than my ARs, but again, I wear ear pro when shooting.

 

[Arizona_Mike]

The muzzle is closer too.

Mike

 

[W.E.G.]

The muzzle device accounts for 90% of any variation in perceived "loudness" of a particular round when fired from a barrel of a particular length. The stylishness (or lack thereof) of the fixture in which the barrel is mounted is largely irrelevant as it pertains to the issue of perceived loudness.

 

[Jackal]

You may perceive it to be a little louder, but I bet if it was measured, there would be little difference. I'd imagine that the choice of muzzle brakes would make a far larger impact than the muzzle being a couple inches closer to the shooter. I cant tell the difference in loudness between a 20" AR or a 16" barreled one.

 

[Inebriated]

The muzzle is closer to your ears with a bullpup. As mentioned, they're not as bad as an SBR in the same cartridge, though.

 

[tahunua001]

it's not that they are louder, it's that the muzzle is a lot closer to your face.

 

[briansmithwins]

No difference that I can detect when using the same ammo and flash hiders between my conventional rifles (16 and 20" barrels) and the FS2000 or AUG.

My AK with the gill slot type muzzle break is much louder than any bullpup I've fired.

BSW

 

[W L Johnson]

it's not that they are louder, it's that the muzzle is a lot closer to your face.

Never really noticed that having that big of an effect, noise seem on par with my ARs. Now a brake could change that.

 

[FrankCastleThePunisher]

I haven't really noticed any perceptible difference with my Tavor and Steyr Aug from the
AR 15's.

 

[Art Eatman]

If the measuring device is at your ear, the closer the source of the sound, the higher the dB level at your ear. Sound attenuates with distance and "perceived noise level" is not relevant to the Physics.

 

[MErl]

Do bullpups also tend to shorter 16" minimum barrels to keep the package small? That'll push up noise quite a bit compared to longer barrels.

 

[briansmithwins]

Do bullpups also tend to shorter 16" minimum barrels to keep the package small?

The new AUGs ship with 16" barrels but 20" are available too. Most of the Tavors I see have 18" barrels.

BSW

 

[Paul7]

You may perceive it to be a little louder, but I bet if it was measured, there would be little difference. I'd imagine that the choice of muzzle brakes would make a far larger impact than the muzzle being a couple inches closer to the shooter. I cant tell the difference in loudness between a 20" AR or a 16" barreled one.

I definitely can tell the difference, which is why my ARs are 20". Years ago that length would be seen as a carbine, I don't get the rational with the shorter barrels.

 

[briansmithwins]

I don't get the rational with the shorter barrels.

Lighter and easier to maneuver when fighting in somebody's house and/or getting into and out of vehicles all day long.

Not all rifle shooting happens on sunny days on known distance ranges involving a shooting jacket and big round high contrast targets.

BSW

 

[PedalBiker]

For a given barrel length an muzzle treatment the bullpup will be the same loudness. However, putting the muzzle closer to your ear is a bad thing. Sound decreases with the square of distance - 2x the distance = 1/4 x the sound power.

One advantage of a bullpup is that for a given barrel length the gun can be a lot shorter, so you can have a 20" barreled bullpup that is just as manuverable as a 14" conventional rifle, plus the longer barrel gives the gas more time to expand an cool so it has less muzzle blast.

If we were smarter we'd have effective suppressor technology that would protect hearing without putting a huge can on the end of our guns. Even 12-20 dB suppression would make a huge difference in hearing loss while the gun would still be "loud" enough to make the gun haters happy.

Our government is deliberately causing us harm with current suppressor laws.

 

[Pete D.]

As above.
Sound intensity from a "point source", like the muzzle of a gun, will follow the inverse square law whether source of the sound is moved away or moved toward the ear.
If the muzzle is 20" away from your ear and you move it so that it is 10" from your ear, the intensity of the sound will increase by the factor of four (400%).
Pete.

 

[JustinJ]

Location of the action is not the issue. As mentioned its distance between ear and muzzle. The type of muzzle device will of course make a big difference. I have a 16" AUG with the same flash hider as one of my 16" AR's. With hearing protection I can't tell the difference. The only time I shoot either without hearing protection is with my silencer. The AR is definitely quieter with my can but this has much more to do with the way the AUG vents excess gas. If used once in an emergency one is not going to suffer noticeably more hearing damage with a bullpup than AR.

 

[blindhog1964]

I have a uts15 and I don't notice it to be louder to me than my mossberg 500 with I think a 28" barrel.

 

[Telekinesis]

If we were smarter we'd have effective suppressor technology that would protect hearing without putting a huge can on the end of our guns. Even 12-20 dB suppression would make a huge difference in hearing loss while the gun would still be "loud" enough to make the gun haters happy.

Our government is deliberately causing us harm with current suppressor laws.

It has nothing to do with being smarter and everything to do with the regulatory environment. If you're going to have to pay $200 and wait 6-9 months, you want to get the best suppressor available, not something that'll just knock a few dB off and still require ear pro to be hearing safe. There is a small market for micro suppresses already, but I don't think even those guys would be interested in something that wouldn't be hearing safe for the first few shots (using up water and wipes).

Even with current manufacturing methods you can integrally suppress a lot of weapons so that they would be quiet while still not having a can on the end. And I believe the Russians even created internally suppressed ammunition (which is considered a suppressor by the ATF and requires serial numbers and transfer taxes for each round...)

Regarding the Bulpup volume question, as long as you're using similar barrel lengths between the standard rifle and the Bulpup, I doubt there would be too much difference between sound levels of each. Distance to your ear will technically change the levels slightly, but I think you'd be hard pressed to tell that it was appreciably louder. If you use either without ears (or a can), you'll definitely be in for hearing damage.

 

[benEzra]

In a bullpup design, the action (or the place where the explosion sets the bullet in motion) is right at the shooter's ear....physics tells us the proximity to the ear is extremely important in measuring volume.

The noise comes from the high-pressure gases escaping from the muzzle, not the burning of powder in the chamber.

In general, several things determine the loudness of a firearm:

(1) the pressure of the gas venting to the atmosphere (for a typical centerfire rifle, that's going to be in the ballpark of 3000 psi at the instant the bullet exits the muzzle); longer barrels mean less pressure and shorter barrels mean more pressure when the bullet exits;

(2) the bore diameter (bigger is louder, since a bigger bore vents more gas if the pressure is the same);

(3) a muzzle brake, if present (brakes increase the sound produced and also direct more of it toward the shooter's ears);

(4) a barrel-cylinder gap, if present (in revolvers; gas pressure at the gap can be 10,000-30,000 psi, making gap venting very loud);

(5) how close the muzzle is to your ear.

The bullpup design reduces (1) by giving you more barrel length for the same size rifle. So for the same size rifle, a bullpup should actually be a little quieter because it will have a longer barrel.

However, if you compare the same size barrel (16" barreled bullpup vs. 16" barreled AR, for example), the bullpup might seem a little louder because the muzzle is a little closer to your ear.