Shooting down gun myths, Muzzle Brakes

Discussion in 'General Rifle Discussion' started by sarge_257, Oct 19, 2010.

  1. sarge_257

    sarge_257 New Member

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    This is going to be a very controversial post. I expect to get a lot of comments and disagreements. That is OK, I have enough proof to satisfy me.


    Shooting down gun myths is one of my favorite things to do. I love it when someone tells me something about guns and then I start asking questions. Very soon I find that the 'fact' is a rumor or a heresay from some one that he does not remember. So here goes.
    Muzzle brakes make more noise.

    OK now lets think a while. What makes the noise? I think I talked about this before in another forum. The bullet does not make the noise. The powder gas make the noise. So a certain amount of powder gas should produce a certain amount of noise. Right? Of course there are varibles. The size of the barrel caliber will make a difference and the weight of the bullet. Also the burning speed of the powder.
    OK so how is holes in the end of the barrel going to produce more noise than a barrel without holes? Does it produce more powder gas? No, the same amount of powder will make the same amount of noise. Does it direct the noise in a different direction. To some extent but when the normal unvented barrel fires the powder gas goes in all directions, not just forward. The vented muzzle brake actually changes some of the energy of the powder gas into forward thrust, so by that, it should have less noise rather than more noise. What do you think?
    Heh heh heh
    Sarge
     
  2. AusLach

    AusLach New Member

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    I don't believe that a muzzle brake will make the firearm actually louder, however the noise level perceived by the shooter will probably be increased. Noise and pressure waves that are normally projected forward and away from the shooter are now allowed to escape the barrel in different directions and sometimes back toward the ear of the person behind the trigger.

    Don't forget that ported barrels also effectively shorten the barrel length, and this allows more powder to be changed into noise energy instead of mechanical energy which propels the bullet. This translates to more noise.
     

  3. kenhesr

    kenhesr New Member

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    +1 on what Auslach said. Its the redirection of the blast that causes it to be perceived to be louder.

    Army Guide - Muzzle Brake

    My favorite brake isn't any louder for the shooter, but if you are a couple feet to either side and to the rear of the shooter, it will rock your world!

    Big thing is that it really works. At 200 yds with a 40x scope you can watch the 5.56 rd hit the target. The bbl will not move at all!

    [​IMG]

    Good question sarge! :)
     
  4. zhuk

    zhuk New Member

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    ^Seeing the round hit the target...that would be an experience. Pity I can't have the chance.



    Would like to see this in action...ditto the above :rolleyes:


    [​IMG]
     
  5. Shade

    Shade New Member

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    I will agree with everyone, total noise produced by a firearm with or without
    a muzzle brake is the same or close to the same. The difference is where
    that noise is directed.

    Without a muzzle brake the majority of the sound energy is directed
    down range with the bullet. With various muzzle brake, the noise, as
    is the majority of gasses, are redirected back in the general direction
    of the shooter or observers depending on the design of the muzzle brake.
    Therefore observed or percevied noise is louder toward the shooter with a
    muzzle brake. If you were stupid enough to observe the noise from a rifle
    down range that did not have a muzzle brake it would be similar to that of a
    rifle with a muzzle brake from behind the rifle.

    Another way to look at it muzzle brakes reduce felt recoil, by using the mass
    of the ejected gasses to reduce recoil, will if you are not feeling the recoil
    that energy has to go somewhere. The first law of thermodynamics must be
    observed; The first law mandates conservation of energy.
     
  6. JTJ

    JTJ Well-Known Member Supporter

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    If you are using a muzzel brake on a high power rifle at the range, Please shield the blast from the shooter next to you. Aside from noise you can cause eye damage from the deflected muzzle blast. I had to make a trip to the Opthamologist after a large bore shooter with a muzzle brake moved in next to me. The blast went bhind my glasses.
     
  7. c3shooter

    c3shooter Administrator Staff Member

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    The traditional "arrowhead" muzzle brake on a Barrett will blow your ball cap off. Are we speaking of true muzzle brakes, or flash suppressors?
     
  8. Shade

    Shade New Member

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    I was discussing true muzzle brakes. Flash suppressors are completely different animal.
     
  9. R-BOLT

    R-BOLT New Member

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    I was hog hunting with some buddies, one had a muzzle brake on his rifle. We came across a hog he wanted, so we set up with me beside him. He shot that hog, and I about wrapped his rifle around his neck. Needless to say he unscrewed the brake and left it off the rest of the hog hunt. I will not hunt with anyone with a muzzle brake on their rifle. My $.02 on brakes.
     
  10. Fisherking

    Fisherking New Member

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    +1 on what ever one else said. The redirection of the gasses and sound will be precived as lowder.
    F.K.
     
  11. Highpower

    Highpower New Member

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    Say what? 40x???
     
  12. Sampleman

    Sampleman New Member

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    Yea Ney

    First, the bullet does make noise. There is a sonic wave on any supersonic bullet which creates the crack. This is why weapons truly intended to be silent are down loaded to subsonic bullets. On a .22 rifle, this can be the majority of the sound heard at a distance. Should muzzle brakes effect this in any way? I can't think of how.

    Second, the way that gas exands directly relates to how much noise is created. Without a muzzle brake, the predominent gas expansion is forward forming a cone. The gas molecules travelling at 2500 feet per second don't instantly complete a 90 degree turn. This in turn projects most of the noise forward. Anyone who has strayed past the plane of a muzzle knows this. It gets much louder. A muzzle brake completely changes this dynamic, refocusing the gas and thus sound perpendicularly by way of physical restriction. This absolutely changes the sound level of the firearm to those around and behind it.

    Believe what you want, but if you set up on a bench next to a .300 Mag with a muzzle brake, secure all of your loose ammo and double muff.
     
  13. kenhesr

    kenhesr New Member

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    AHHH, thats just my shorthand for a fixed power scope, non-variable. 40x means 40 power magnification in the group I shoot with. I probably should have taken the time to type in the front objective ie; 40x52mm like the March 40xED scope, 40x45mm with the Leupold LEU53436 or 36x44mm Tasco World Class.

    I should also explain that I was referring to shooting from bags & a rest. I'm not that good a shot!:eek:

    The purpose of my reply was more about the brake in the picture than the scope. That brake is on a standard E.R. Shaw 24" barreled AR-15. With a 40 or even a 36 power scope, from a rest at 200 yds you can read the print on a beer can. With LC77 FMJ 5.56 surplus ball when you fire the rd, the view in the scope stays the same, you can watch the bullet hit the can thru the scope. Like shooting a .22lr at 50 yds with a 3x9x40mm scope. Kinda fun!!

    I also have an AR set up with a 24" E.R. Shaw varmint Bull bbl but no brake, just a target crown. With a 40 power scope at 200 yds, forget it. You will hit where you aimed but the rifle moves enough from recoil, even on bags, you can't see the impact thru the scope.

    I've been messing with weapons for so darn long I just Assume everybody knows what I mean. Wasn't trying to confuse ya, Ken
     
  14. Highpower

    Highpower New Member

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    I'll have to remember that next time I need to read a newspaper from 2 football fields away! ;)
     
  15. kenhesr

    kenhesr New Member

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    LOL!! I don't think I can read too much of the fine print, but you sure can pick which part of the BUDWEISER you want to hit.:D

    Although they claim you can see a 6mm hole in a 600 yd target with the March 40xED scope, but for $2100.00 I think I'll stick with my 200 yd beer can killers. Take care, Ken
     
  16. mrm14

    mrm14 Active Member

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    "Believe what you want, but if you set up on a bench next to a .300 Mag with a muzzle brake, secure all of your loose ammo and double muff."

    You mean one like this?:D

    web[1].jpg
     
  17. Johnny45

    Johnny45 New Member

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    Yeah...I thought it was pretty much taken for granted that a true muzzle brake increases the actual decibels directed back towards the shooters ear, and even more so to the folks standing next to them. I don't think that really counts as a "myth". It's just fact.
    Now, me, I'll hazard this...a muzzle brake, in order to be a real muzzle brake, must direct energy REARWARD in order to counteract the recoil of the cartridge. The bullet causes the actual recoil...all pressure is equal inside the chamber, and the bullet and bolt "shove" each other away from them, which pushes the whole gun back into your arm. The MUZZLE BRAKE is designed to catch some of the gas, and direct it rearward, to provide JET THRUST of a sort in the opposite direction of the recoil. Familiar at all with the principle of the "recoiless-rifle" (the large-caliber, military weapon)? A muzzle brake replicates on a smaller, and far less effective scale the equalizing effect of a blast in the opposite vector to the recoil of the bullet accelerating out the barrel.
    Since the entire rifle is such a big, heavy chunk of metal and wood (or plastic, if that's your "thing"), it takes the impulse far slower than tiny little bullet. That means, given an equal force, it takes far longer to accelerate than the bullet does. The cartridge goes off...the bullet accelerates up the barrel, and the gun almost imperceptibly begins to move rearward, building speed as the bullet nears the muzzle.
    As the bullet reaches the muzzle-brake ports, the high pressure gas is directed to the REAR, providing a very quick thrust or impulse to the rear, taking a lot of "oomph" out if the building acceleration of the gun/stock.

    In conclusion, not only does a true muzzle brake truly direct blast (and sound) to the rear (not 90deg from the muzzle), but I doubt even a plain-muzzled rifle actually vents to a true 90deg. Ever seen muzzle-flash from a gun without a flash suppressor? (i.e. not the movie-gooks shooting back with their AK's)? It tends to spear out the front, with a relatively small blast around the muzzle itself. I suspect that flash suppressors do actually increase the heard-noise level to a small extent, since they DO direct some of the gasses outward...but they generally also provide a small area for the gasses to expand slightly before exiting the ports...and the lower the pressure, the slower(quieter) the escaping gas will be.
    Of course, sound waves travel slightly different from the blast (that's why they still sound loud when you shoot plain-muzzled guns), but the vector of the blast makes a difference.
    Listen to a loud (or even quiet, if you listen close) jet fly past at low level...as it comes it, it sounds relatively quiet (and this is ignoring the Doppler change in the pitch). It gets a bit louder as it gets about 15-20deg overhead, but when it passes 90deg...hooly shyte!!! Now imagine a jet with a muzzle brake directing that force forward?
    LOL, in fact, that reminds me of the Harrier attack fighter(whatever version you want...GR.1 through AV-8B+) is notoriously loud to those on the ground, particularly when hovering or in V/STOL mode. Any guesses why? Because the jets are facing DOWN, toward the ground. It's even very loud in horizontal flight, due to the relatively small nozzle area to mass-flow...i.e. high speed exhausts, the same reason that older turbojets are so god-awful loud (of course, the Harrier is a turboFAN...turbojets are inherently loud, but the Pegasus turbofan in the Harrier is only loud because of it's nozzle configuration.
     
  18. mobius

    mobius New Member

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    +1 Sampleman

    Think of this for a simple example. When you blow out you make a certain amount of noise, not much. Blow the same volume of air across a sharp edge and your noise level increases. That is not to say a muzzle brake will necessarily increase the volume of sound, though it easily could and probably will.

    Fred
    Molon Labe
     
  19. lonyaeger

    lonyaeger New Member

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    A conspicuous absence of Tango in this thread......?
     
  20. mrm14

    mrm14 Active Member

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    What I think is that the shooters either side of my brake are getting more percussion than the actual sound. Not to say that the report they hear doesn't seem louder because it does from what they would be otherwise hearing from their position with an unbraked rifle. That percussion is pretty hard on the ear drum even with muffs on. I think it's the percussion wave that gives a braked rifle it's "Bark". When I'm shooting my braked rifle I can't tell the difference in precieved decibles between the brake being on or off the rifle. Also, don't feel much if any of the percussion. Probably because I'm behind the damn thing.